fix: resolve CI lint errors and flaky tests

- analytics.go: use min() builtin, remove unused filteredSessions
- codex.go: use strings.SplitSeq for efficiency (modernize lint)
- server_test.go: remove unused seedSessionWithMessages
- watcher_test.go: poll for nested path instead of counting
  onChange calls, fixing race on slow CI runners
- db_test.go: close raw DB before concurrent Opens to avoid
  Windows file locking in TestMigrationRace

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

Author: wesm

internal/db/analytics.go

@@ -32,10 +32,7 @@ func queryChunked(
 	fn func(chunk []string) error,
 ) error {
 	for i := 0; i < len(ids); i += maxSQLVars {
-		end := i + maxSQLVars
-		if end > len(ids) {
-			end = len(ids)
-		}
+		end := min(i+maxSQLVars, len(ids))
 		if err := fn(ids[i:end]); err != nil {
 			return err
 		}
@@ -398,10 +395,7 @@ func (db *DB) GetAnalyticsSummary(
 			counts = append(counts, c)
 		}
 		sort.Sort(sort.Reverse(sort.IntSlice(counts)))
-		top := 3
-		if len(counts) < top {
-			top = len(counts)
-		}
+		top := min(3, len(counts))
 		topSum := 0
 		for _, c := range counts[:top] {
 			topSum += c
@@ -1150,15 +1144,9 @@ func (db *DB) GetAnalyticsSessionShape(
 	}
 	defer rows.Close()
 
-	type sessInfo struct {
-		id string
-		mc int
-	}
-
 	lengthCounts := make(map[string]int)
 	durationCounts := make(map[string]int)
 	var sessionIDs []string
-	var filteredSessions []sessInfo
 	totalCount := 0
 
 	for rows.Next() {
@@ -1183,8 +1171,6 @@ func (db *DB) GetAnalyticsSessionShape(
 		totalCount++
 		lengthCounts[lengthBucket(mc)]++
 		sessionIDs = append(sessionIDs, id)
-		filteredSessions = append(filteredSessions,
-			sessInfo{id: id, mc: mc})
 
 		if startedAt != nil && endedAt != nil &&
 			*startedAt != "" && *endedAt != "" {

internal/db/db_test.go

@@ -1384,7 +1384,6 @@ func TestMigrationRace(t *testing.T) {
 	if err != nil {
 		t.Fatalf("setup: %v", err)
 	}
-	defer rawDB.Close()
 
 	// Create sessions table without file_hash
 	_, err = rawDB.Exec(`
@@ -1407,6 +1406,10 @@ func TestMigrationRace(t *testing.T) {
 		t.Fatalf("setup schema: %v", err)
 	}
 
+	// Close the raw connection before concurrent opens to avoid
+	// holding a lock on Windows.
+	rawDB.Close()
+
 	// 2. Run concurrent Open
 	// Both should succeed. One will likely hit "duplicate column".
 	errCh := make(chan error, 2)

internal/parser/codex.go

@@ -318,8 +318,7 @@ func extractPatchedFiles(patch string) []string {
 
 	var files []string
 	seen := make(map[string]struct{})
-	lines := strings.Split(patch, "\n")
-	for _, line := range lines {
+	for line := range strings.SplitSeq(patch, "\n") {
 		for _, prefix := range []string{
 			"*** Add File: ",
 			"*** Update File: ",

internal/server/server_test.go

@@ -217,15 +217,6 @@ func (te *testEnv) seedSession(
 	})
 }
 
-func (te *testEnv) seedSessionWithMessages(
-	t *testing.T, id, project string, msgCount int,
-	opts ...func(*db.Session),
-) {
-	t.Helper()
-	te.seedSession(t, id, project, msgCount, opts...)
-	te.seedMessages(t, id, msgCount)
-}
-
 func (te *testEnv) seedMessages(
 	t *testing.T, sessionID string, count int, mods ...func(i int, m *db.Message),
 ) {

internal/sync/watcher_test.go

@@ -139,20 +139,19 @@ func TestWatcherCallsOnChange(t *testing.T) {
 }
 
 func TestWatcherAutoWatchesNewDirs(t *testing.T) {
-	var called atomic.Bool
+	var mu sync.Mutex
+	var allPaths []string
 	done := make(chan struct{}, 1)
 
-	callCount := atomic.Int32{}
-	onChange := func(_ []string) {
-		if callCount.Add(1) >= 2 {
-			if !called.Load() {
-				called.Store(true)
-				done <- struct{}{}
-			}
+	w, dir := startTestWatcher(t, func(paths []string) {
+		mu.Lock()
+		allPaths = append(allPaths, paths...)
+		mu.Unlock()
+		select {
+		case done <- struct{}{}:
+		default:
 		}
-	}
-
-	w, dir := startTestWatcher(t, onChange)
+	})
 
 	subdir := filepath.Join(dir, "newdir")
 	if err := os.Mkdir(subdir, 0o755); err != nil {
@@ -166,14 +165,21 @@ func TestWatcherAutoWatchesNewDirs(t *testing.T) {
 		},
 	)
 
-	path := filepath.Join(subdir, "nested.jsonl")
+	nestedPath := filepath.Join(subdir, "nested.jsonl")
 	if err := os.WriteFile(
-		path, []byte("nested"), 0o644,
+		nestedPath, []byte("nested"), 0o644,
 	); err != nil {
 		t.Fatalf("WriteFile: %v", err)
 	}
 
-	waitWithTimeout(t, done, 5*time.Second, "timed out waiting for nested file change")
+	pollUntil(t, 5*time.Second, 50*time.Millisecond,
+		"timed out waiting for nested file change",
+		func() bool {
+			mu.Lock()
+			defer mu.Unlock()
+			return slices.Contains(allPaths, nestedPath)
+		},
+	)
 }
 
 func TestWatcherStopIsClean(t *testing.T) {