Add CLI availability checks and provider opt-in settings (#39)

* Add CLI availability checks and provider opt-in settings

Detect installed CLI tools (claude, codex, gemini) at startup and let
users enable/disable providers in repo settings. Only installed+enabled
providers appear in Alt+M model cycling and the welcome screen shows
provider status. Moves the task router from wt/taskrouter/ to
bramble/taskrouter/ and refactors it to use the generic Provider
interface so any backend can power routing decisions.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Fix review findings: wiring gaps, timeout, and version noise

- Wire ModelRegistry into session.ManagerConfig so the provider
  availability guard in runSession() is actually enforced
- Add 5s timeout to --version probes so a hanging CLI can't block startup
- Discard stderr in version probes to filter Node.js deprecation warnings
  (fixes gemini showing punycode DeprecationWarning)
- Fix SetEnabledProviders to distinguish nil (all enabled) from empty
  slice (all disabled) so users can actually disable all providers
- Fix NextModel to return current model unchanged when filtered list is
  empty, avoiding selection of an unavailable provider
- Fix integration test to supply a codex provider (required by new API)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Show all color themes as visual grid in settings dialog

Replace the blind left/right theme cycling with a responsive grid of
color swatches. Each swatch shows the theme name in its accent color
and colored dots previewing Running/Error/Idle/Pending/Dim palette
colors. Arrow keys navigate the 2D grid; selected theme still
live-previews across the app.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Fix review findings: nil-means-all bug, registry race, and router panic

- EnabledProviders: use make([]string, 0, ...) so disabling all providers
  returns a non-nil empty slice instead of nil (which means "all enabled")
- ModelRegistry: add sync.RWMutex so Rebuild (UI goroutine) and readers
  (session goroutines) don't race on the filtered slice
- Router.Route: nil-check result before dereferencing result.Error to
  prevent panic when provider returns (nil, nil)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Fix non-installed providers polluting enabled set

Only mark installed providers as enabled in Show() default path, and
filter out non-installed providers from explicit enabledProviders list.
Also compare against installed count (not total) when deciding whether
to return nil ("all enabled") from EnabledProviders().

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* Fix nil-vs-empty provider semantics and code duplication

Addresses remaining review comments:

1. **Fix nil-vs-empty confusion (High Severity)**:
   - Changed EnabledProviders from `[]string` to `*[]string` in Settings
   - nil pointer means "all providers enabled" (default/unset)
   - Non-nil pointer to empty slice means "no providers enabled"
   - This distinction survives JSON round-trip (nil omitted, [] preserved)
   - Updated all consumers to use `enabledProviders == nil` instead of `len() == 0`

2. **Remove unused IsProviderEnabled method**:
   - Method is never called, but kept it for API completeness
   - Added GetEnabledProviders() helper for common access pattern

3. **Fix boxWidth code duplication (Low Severity)**:
   - Extracted dialogBoxWidth() helper method
   - Prevents navigation-rendering mismatch if calculation diverges

Related bugbot findings:
- Fixes "Empty enabled providers treated as all-enabled" (ID: 79b6d740)
- Fixes "JSON omitempty loses all-disabled state" (ID: adb89310)
- Addresses "Duplicated boxWidth calculation" (ID: a3cbc788)

* Fix Show() to correctly distinguish nil vs empty enabled providers

The Show() method was using len(enabledProviders) == 0 to check for
the "all enabled" case, but this matches both nil and empty slices.
According to the Settings design:
- nil means "all enabled" (default/unset)
- empty slice means "all disabled"

Changed to enabledProviders == nil to correctly distinguish these cases.
This prevents the dialog from re-enabling all providers when the user
has explicitly disabled everything.

Fixes the last remaining issue identified in PR review.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: mzhaom

bramble/BUILD.bazel

@@ -8,8 +8,9 @@ go_library(
     deps = [
         "//bramble/app",
         "//bramble/session",
+        "//bramble/taskrouter",
+        "//multiagent/agent",
         "//wt",
-        "//wt/taskrouter",
         "@com_github_charmbracelet_bubbletea//:bubbletea",
         "@com_github_spf13_cobra//:cobra",
         "@org_golang_x_term//:term",

bramble/app/BUILD.bazel

@@ -29,8 +29,9 @@ go_library(
     visibility = ["//bramble:__subpackages__"],
     deps = [
         "//bramble/session",
+        "//bramble/taskrouter",
+        "//multiagent/agent",
         "//wt",
-        "//wt/taskrouter",
         "@com_github_charmbracelet_bubbles//key",
         "@com_github_charmbracelet_bubbles//textarea",
         "@com_github_charmbracelet_bubbles//textinput",

bramble/app/aggregate_cost_test.go

@@ -10,15 +10,15 @@ import (
 )
 
 func TestAggregateCost_Empty(t *testing.T) {
-	m := NewModel(context.Background(), "", "", "", session.NewManager(), nil, nil, 80, 24)
+	m := NewModel(context.Background(), "", "", "", session.NewManager(), nil, nil, 80, 24, nil, nil)
 	cost := m.aggregateCost()
 	if cost != 0.0 {
 		t.Errorf("expected 0.0, got %.4f", cost)
 	}
 }
 
 func TestAggregateCost_MultipleSessions(t *testing.T) {
-	m := NewModel(context.Background(), "", "", "", session.NewManager(), nil, nil, 80, 24)
+	m := NewModel(context.Background(), "", "", "", session.NewManager(), nil, nil, 80, 24, nil, nil)
 	m.sessions = []session.SessionInfo{
 		{Progress: session.SessionProgressSnapshot{TotalCostUSD: 0.0100}},
 		{Progress: session.SessionProgressSnapshot{TotalCostUSD: 0.0250}},
@@ -32,7 +32,7 @@ func TestAggregateCost_MultipleSessions(t *testing.T) {
 }
 
 func TestRenderStatusBar_CostOmittedWhenZero(t *testing.T) {
-	m := NewModel(context.Background(), "", "", "", session.NewManager(), nil, nil, 80, 24)
+	m := NewModel(context.Background(), "", "", "", session.NewManager(), nil, nil, 80, 24, nil, nil)
 	m.sessions = []session.SessionInfo{
 		{Progress: session.SessionProgressSnapshot{TotalCostUSD: 0.0}},
 	}
@@ -43,7 +43,7 @@ func TestRenderStatusBar_CostOmittedWhenZero(t *testing.T) {
 }
 
 func TestRenderStatusBar_CostShownWhenNonZero(t *testing.T) {
-	m := NewModel(context.Background(), "", "", "", session.NewManager(), nil, nil, 80, 24)
+	m := NewModel(context.Background(), "", "", "", session.NewManager(), nil, nil, 80, 24, nil, nil)
 	m.sessions = []session.SessionInfo{
 		{Progress: session.SessionProgressSnapshot{TotalCostUSD: 0.0100}},
 		{Progress: session.SessionProgressSnapshot{TotalCostUSD: 0.0250}},

bramble/app/filetree_open_test.go

@@ -93,7 +93,7 @@ func TestAbsSelectedPath_PathTraversal(t *testing.T) {
 }
 
 func TestHandleKeyPress_EnterInSplitPane(t *testing.T) {
-	m := NewModel(context.Background(), "/tmp/wt", "test-repo", "code", session.NewManager(), nil, nil, 80, 24)
+	m := NewModel(context.Background(), "/tmp/wt", "test-repo", "code", session.NewManager(), nil, nil, 80, 24, nil, nil)
 
 	// Set up split pane with file tree
 	m.splitPane.Toggle()
@@ -128,7 +128,7 @@ func TestHandleKeyPress_EnterInSplitPane(t *testing.T) {
 }
 
 func TestHandleKeyPress_EnterInSplitPane_NoFile(t *testing.T) {
-	m := NewModel(context.Background(), "/tmp/wt", "test-repo", "code", session.NewManager(), nil, nil, 80, 24)
+	m := NewModel(context.Background(), "/tmp/wt", "test-repo", "code", session.NewManager(), nil, nil, 80, 24, nil, nil)
 
 	// Set up split pane with file tree
 	m.splitPane.Toggle()
@@ -158,7 +158,7 @@ func TestHandleKeyPress_EnterInSplitPane_NoFile(t *testing.T) {
 }
 
 func TestHandleKeyPress_EnterNotInSplitPane(t *testing.T) {
-	m := NewModel(context.Background(), "/tmp/wt", "test-repo", "code", session.NewManager(), nil, nil, 80, 24)
+	m := NewModel(context.Background(), "/tmp/wt", "test-repo", "code", session.NewManager(), nil, nil, 80, 24, nil, nil)
 
 	// Don't activate split pane
 	// Send Enter key
@@ -177,7 +177,7 @@ func TestBuildHelpSections_SplitPaneActive(t *testing.T) {
 	mgr := session.NewManagerWithConfig(session.ManagerConfig{
 		SessionMode: session.SessionModeTUI,
 	})
-	m := NewModel(context.Background(), "/tmp/wt", "test-repo", "code", mgr, nil, nil, 80, 24)
+	m := NewModel(context.Background(), "/tmp/wt", "test-repo", "code", mgr, nil, nil, 80, 24, nil, nil)
 	m.splitPane.Toggle()
 
 	sections := buildHelpSections(&m)
@@ -276,7 +276,7 @@ func TestHandleKeyPress_UpDownNavigatesSessionListInTmuxSplitRightFocus(t *testi
 	worktrees := []wt.Worktree{
 		{Branch: "main", Path: "/tmp/wt/main"},
 	}
-	m := NewModel(context.Background(), "/tmp/wt", "test-repo", "", mgr, nil, worktrees, 80, 24)
+	m := NewModel(context.Background(), "/tmp/wt", "test-repo", "", mgr, nil, worktrees, 80, 24, nil, nil)
 
 	// Start sessions so navigation has items
 	_, _ = mgr.StartSession(session.SessionTypePlanner, "/tmp/wt/main", "session A", "")
@@ -443,7 +443,7 @@ func TestBuildHelpSections_SplitPaneInactive(t *testing.T) {
 	mgr := session.NewManagerWithConfig(session.ManagerConfig{
 		SessionMode: session.SessionModeTUI,
 	})
-	m := NewModel(context.Background(), "/tmp/wt", "test-repo", "code", mgr, nil, nil, 80, 24)
+	m := NewModel(context.Background(), "/tmp/wt", "test-repo", "code", mgr, nil, nil, 80, 24, nil, nil)
 	// Don't activate split pane
 
 	sections := buildHelpSections(&m)

bramble/app/helpoverlay.go

@@ -293,7 +293,7 @@ func buildHelpSections(m *Model) []HelpSection {
 	// General
 	gen := HelpSection{Title: "General"}
 	gen.Bindings = append(gen.Bindings,
-		HelpBinding{"Ctrl-,", "Open settings"},
+		HelpBinding{"Ctrl+L", "Open settings"},
 		HelpBinding{"Esc", "Clear error / close overlay"},
 		HelpBinding{"q", "Quit Bramble"},
 		HelpBinding{"Ctrl-C", "Force quit"},

bramble/app/helpoverlay_test.go

@@ -17,7 +17,7 @@ func TestHelpOverlayContextAwareness(t *testing.T) {
 	defer mgr.Close()
 
 	// Case 1: No worktree, no session -> Sessions section should be minimal
-	m := NewModel(ctx, "/tmp/wt", "test-repo", "", mgr, nil, nil, 80, 24)
+	m := NewModel(ctx, "/tmp/wt", "test-repo", "", mgr, nil, nil, 80, 24, nil, nil)
 	sections := buildHelpSections(&m)
 
 	// Should have navigation and general sections
@@ -39,7 +39,7 @@ func TestHelpOverlayContextAwareness(t *testing.T) {
 	worktrees := []wt.Worktree{
 		{Branch: "feature-auth", Path: "/tmp/wt/feature-auth"},
 	}
-	m2 := NewModel(ctx, "/tmp/wt", "test-repo", "", mgr, nil, worktrees, 80, 24)
+	m2 := NewModel(ctx, "/tmp/wt", "test-repo", "", mgr, nil, worktrees, 80, 24, nil, nil)
 	sections2 := buildHelpSections(&m2)
 
 	hasWorktrees := false
@@ -57,7 +57,7 @@ func TestHelpOverlayContextAwareness(t *testing.T) {
 	}
 
 	// Case 3: Previous focus was dropdown -> Dropdown section should appear
-	m3 := NewModel(ctx, "/tmp/wt", "test-repo", "", mgr, nil, worktrees, 80, 24)
+	m3 := NewModel(ctx, "/tmp/wt", "test-repo", "", mgr, nil, worktrees, 80, 24, nil, nil)
 	m3.helpOverlay.previousFocus = FocusWorktreeDropdown
 	sections3 := buildHelpSections(&m3)
 
@@ -77,7 +77,7 @@ func TestHelpOverlayFocusRestoration(t *testing.T) {
 	mgr := session.NewManagerWithConfig(session.ManagerConfig{SessionMode: session.SessionModeTUI})
 	defer mgr.Close()
 
-	m := NewModel(ctx, "/tmp/wt", "test-repo", "", mgr, nil, nil, 80, 24)
+	m := NewModel(ctx, "/tmp/wt", "test-repo", "", mgr, nil, nil, 80, 24, nil, nil)
 
 	// Open help from FocusOutput
 	m.helpOverlay.previousFocus = FocusOutput
@@ -98,7 +98,7 @@ func TestHelpOverlayKeyHandling(t *testing.T) {
 	mgr := session.NewManagerWithConfig(session.ManagerConfig{SessionMode: session.SessionModeTUI})
 	defer mgr.Close()
 
-	m := NewModel(ctx, "/tmp/wt", "test-repo", "", mgr, nil, nil, 80, 24)
+	m := NewModel(ctx, "/tmp/wt", "test-repo", "", mgr, nil, nil, 80, 24, nil, nil)
 	m.focus = FocusHelp
 	m.helpOverlay.previousFocus = FocusOutput
 
@@ -145,7 +145,7 @@ func TestHelpOverlayRendering(t *testing.T) {
 	worktrees := []wt.Worktree{
 		{Branch: "feature-auth", Path: "/tmp/wt/feature-auth"},
 	}
-	m := NewModel(ctx, "/tmp/wt", "test-repo", "", mgr, nil, worktrees, 80, 24)
+	m := NewModel(ctx, "/tmp/wt", "test-repo", "", mgr, nil, worktrees, 80, 24, nil, nil)
 
 	sections := buildHelpSections(&m)
 	m.helpOverlay.SetSections(sections)
@@ -182,20 +182,20 @@ func TestHelpOverlayIncludesSettingsBinding(t *testing.T) {
 	mgr := session.NewManagerWithConfig(session.ManagerConfig{SessionMode: session.SessionModeTUI})
 	defer mgr.Close()
 
-	m := NewModel(ctx, "/tmp/wt", "test-repo", "", mgr, nil, nil, 80, 24)
+	m := NewModel(ctx, "/tmp/wt", "test-repo", "", mgr, nil, nil, 80, 24, nil, nil)
 	sections := buildHelpSections(&m)
 
 	found := false
 	for _, section := range sections {
 		for _, binding := range section.Bindings {
-			if binding.Key == "Ctrl-," {
+			if binding.Key == "Ctrl+L" {
 				found = true
 				break
 			}
 		}
 	}
 	if !found {
-		t.Fatal("expected Ctrl-, settings binding in help sections")
+		t.Fatal("expected Ctrl+L settings binding in help sections")
 	}
 }
 
@@ -230,7 +230,7 @@ func TestBuildHelpSectionsWithSession(t *testing.T) {
 	worktrees := []wt.Worktree{
 		{Branch: "feature-auth", Path: "/tmp/wt/feature-auth"},
 	}
-	m := NewModel(ctx, "/tmp/wt", "test-repo", "", mgr, nil, worktrees, 80, 24)
+	m := NewModel(ctx, "/tmp/wt", "test-repo", "", mgr, nil, worktrees, 80, 24, nil, nil)
 
 	// Add a session
 	sessionID, err := mgr.StartSession(session.SessionTypePlanner, "/tmp/wt/feature-auth", "test plan", "")

bramble/app/integration/BUILD.bazel

@@ -13,7 +13,8 @@ go_test(
     deps = [
         "//bramble/app",
         "//bramble/session",
-        "//wt/taskrouter",
+        "//bramble/taskrouter",
+        "//multiagent/agent",
         "@com_github_stretchr_testify//assert",
         "@com_github_stretchr_testify//require",
     ],

bramble/app/integration/route_task_test.go

@@ -13,7 +13,8 @@ import (
 
 	"github.com/bazelment/yoloswe/bramble/app"
 	"github.com/bazelment/yoloswe/bramble/session"
-	"github.com/bazelment/yoloswe/wt/taskrouter"
+	"github.com/bazelment/yoloswe/bramble/taskrouter"
+	"github.com/bazelment/yoloswe/multiagent/agent"
 )
 
 // TestRouteTaskWithRealRouter verifies that the TUI wiring to the real
@@ -22,10 +23,10 @@ func TestRouteTaskWithRealRouter(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
 	defer cancel()
 
-	// Start a real router
+	// Start a real router with a codex provider
 	router := taskrouter.New(taskrouter.Config{
-		WorkDir: t.TempDir(),
-		NoColor: true,
+		Provider: agent.NewCodexProvider(),
+		WorkDir:  t.TempDir(),
 	})
 	router.SetOutput(io.Discard)
 
@@ -37,7 +38,7 @@ func TestRouteTaskWithRealRouter(t *testing.T) {
 	mgr := session.NewManagerWithConfig(session.ManagerConfig{SessionMode: session.SessionModeTUI})
 	defer mgr.Close()
 
-	m := app.NewModel(ctx, "/tmp/wt", "test-repo", "", mgr, router, nil, 80, 24)
+	m := app.NewModel(ctx, "/tmp/wt", "test-repo", "", mgr, router, nil, 80, 24, nil, nil)
 
 	// Use RouteTask (exported from taskmodal.go) directly to verify wiring
 	req := taskrouter.RouteRequest{

bramble/app/model.go

@@ -12,8 +12,9 @@ import (
 	"github.com/mattn/go-runewidth"
 
 	"github.com/bazelment/yoloswe/bramble/session"
+	"github.com/bazelment/yoloswe/bramble/taskrouter"
+	"github.com/bazelment/yoloswe/multiagent/agent"
 	"github.com/bazelment/yoloswe/wt"
-	"github.com/bazelment/yoloswe/wt/taskrouter"
 )
 
 // FocusArea indicates which area has focus.
@@ -59,6 +60,8 @@ type Model struct { //nolint:govet // fieldalignment: readability over padding f
 	repoSettingsDialog    *RepoSettingsDialog
 	styles                *Styles
 	settings              Settings
+	providerAvailability  *agent.ProviderAvailability
+	modelRegistry         *agent.ModelRegistry
 	inputArea             *TextArea
 	splitPane             *SplitPane
 	fileTree              *FileTree
@@ -88,7 +91,7 @@ type Model struct { //nolint:govet // fieldalignment: readability over padding f
 // render shows branch names immediately without waiting for an async refresh.
 // width/height set the initial terminal dimensions so the first View() can
 // render a proper layout without waiting for WindowSizeMsg.
-func NewModel(ctx context.Context, wtRoot, repoName, editor string, sessionManager *session.Manager, taskRouter *taskrouter.Router, initialWorktrees []wt.Worktree, width, height int) Model {
+func NewModel(ctx context.Context, wtRoot, repoName, editor string, sessionManager *session.Manager, taskRouter *taskrouter.Router, initialWorktrees []wt.Worktree, width, height int, providerAvailability *agent.ProviderAvailability, modelRegistry *agent.ModelRegistry) Model {
 	if editor == "" {
 		editor = "code"
 	}
@@ -103,32 +106,50 @@ func NewModel(ctx context.Context, wtRoot, repoName, editor string, sessionManag
 	}
 	styles := NewStyles(palette)
 
+	// Resolve default models from the registry (prefer claude if available)
+	defaultPlanModel := "opus"
+	defaultBuildModel := "sonnet"
+	if modelRegistry != nil {
+		if m, ok := modelRegistry.ModelByID("opus"); ok {
+			defaultPlanModel = m.ID
+		} else if models := modelRegistry.Models(); len(models) > 0 {
+			defaultPlanModel = models[0].ID
+		}
+		if m, ok := modelRegistry.ModelByID("sonnet"); ok {
+			defaultBuildModel = m.ID
+		} else if models := modelRegistry.Models(); len(models) > 0 {
+			defaultBuildModel = models[0].ID
+		}
+	}
+
 	m := Model{
-		ctx:                ctx,
-		wtRoot:             wtRoot,
-		repoName:           repoName,
-		editor:             editor,
-		sessionManager:     sessionManager,
-		taskRouter:         taskRouter,
-		styles:             styles,
-		settings:           settings,
-		themePicker:        NewThemePicker(),
-		repoSettingsDialog: NewRepoSettingsDialog(),
-		focus:              FocusOutput,
-		width:              width,
-		height:             height,
-		defaultPlanModel:   "opus",
-		defaultBuildModel:  "sonnet",
-		worktreeDropdown:   wtDropdown,
-		sessionDropdown:    NewDropdown(nil),
-		taskModal:          NewTaskModal(),
-		toasts:             NewToastManager(),
-		helpOverlay:        NewHelpOverlay(),
-		allSessionsOverlay: NewAllSessionsOverlay(),
-		inputArea:          NewTextArea(),
-		splitPane:          NewSplitPane(),
-		fileTree:           NewFileTree("", nil),
-		scrollPositions:    make(map[session.SessionID]int),
+		ctx:                  ctx,
+		wtRoot:               wtRoot,
+		repoName:             repoName,
+		editor:               editor,
+		sessionManager:       sessionManager,
+		taskRouter:           taskRouter,
+		providerAvailability: providerAvailability,
+		modelRegistry:        modelRegistry,
+		styles:               styles,
+		settings:             settings,
+		themePicker:          NewThemePicker(),
+		repoSettingsDialog:   NewRepoSettingsDialog(),
+		focus:                FocusOutput,
+		width:                width,
+		height:               height,
+		defaultPlanModel:     defaultPlanModel,
+		defaultBuildModel:    defaultBuildModel,
+		worktreeDropdown:     wtDropdown,
+		sessionDropdown:      NewDropdown(nil),
+		taskModal:            NewTaskModal(),
+		toasts:               NewToastManager(),
+		helpOverlay:          NewHelpOverlay(),
+		allSessionsOverlay:   NewAllSessionsOverlay(),
+		inputArea:            NewTextArea(),
+		splitPane:            NewSplitPane(),
+		fileTree:             NewFileTree("", nil),
+		scrollPositions:      make(map[session.SessionID]int),
 	}
 
 	// Sync placeholder colors with the loaded theme (NewTextArea defaults to "245")
@@ -758,6 +779,15 @@ func (m *Model) scheduleToastExpiry() tea.Cmd {
 	})
 }
 
+// providerStatusList returns provider statuses for UI display.
+// Returns nil if no availability info is configured.
+func (m *Model) providerStatusList() []agent.ProviderStatus {
+	if m.providerAvailability == nil {
+		return nil
+	}
+	return m.providerAvailability.AllStatuses()
+}
+
 // applyTheme rebuilds styles from a palette and recreates the markdown renderer.
 func (m *Model) applyTheme(palette ColorPalette) {
 	m.styles = NewStyles(palette)