feat: add custom commands for tree view context menu

Allow users to configure external commands (e.g., open in Ghostty, Zed,
Terminal.app) triggered from the tree view context menu via two new settings:
- customCommands.directory: for worktree/repository items
- customCommands.workspace: for workspace file items

Each command supports template variables ({name}, {branch}, {ref}, {head},
{path}, {dir}, {worktree}) and optional environment variables. Commands are
shown in a QuickPick and spawned as fire-and-forget child processes.

Also adds {dir} template variable for workspace items (parent directory).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: VdustR

.changeset/custom-commands.md

@@ -0,0 +1,5 @@
+---
+"git-work-grove": minor
+---
+
+Add custom commands: configure external commands (e.g., open in Ghostty, Zed) triggered from the tree view context menu. Supports template variables for dynamic arguments and environment variables.

.vscodeignore

@@ -1,5 +1,6 @@
 .vscode/**
 .vscode-test/**
+.worktrees/**
 src/**
 node_modules/**
 .changeset/**

CLAUDE.md

@@ -25,6 +25,7 @@ Design specs live in `docs/spec/`. These are the **source of truth** for how fea
 | `docs/spec/open-behavior.md` | Open modes, URI resolution, click handling |
 | `docs/spec/open-in-terminal.md` | CWD resolution, terminal naming, prunable guard |
 | `docs/spec/empty-states.md` | Git unavailable, no repository, no worktrees messages |
+| `docs/spec/custom-commands.md` | Custom commands: settings, execution, context menu |
 
 ## The 4 Fundamental Types
 

README.md

@@ -36,6 +36,7 @@ If VS Code or GitLens ever ships proper `.code-workspace` support for worktrees,
 - **Favorites** — Pin any item (repository, worktree, workspace file) to the top with drag-and-drop reordering
 - **Current indicator** — Green icon and badge highlight the currently open item
 - **Customizable templates** — Full control over labels and descriptions for all 8 item types
+- **Custom Commands** — Define your own context menu commands with template variable support
 - **Open in Terminal** — Right-click to open a terminal at any worktree or workspace file location
 - **Prune** — Clean up stale worktree records
 - **Live updates** — FileSystemWatcher detects worktree changes automatically
@@ -62,6 +63,7 @@ Right-click any item in the tree to access:
 | **Open in Current Window** | Opens in the current VS Code window |
 | **Open in Terminal** | Opens a terminal at the item's location |
 | **Reveal in Finder** | Opens the item's location in your OS file manager |
+| **Custom Commands...** | Runs a user-defined command (when configured) |
 | **Copy Name** | Copy the item's display name to clipboard |
 | **Copy Path** | Copy the item's filesystem path to clipboard |
 
@@ -113,9 +115,35 @@ Open VS Code Settings (`Cmd+,` / `Ctrl+,`) and search for `git-work-grove`:
 | `git-work-grove.openBehavior` | `ask` \| `newWindow` \| `currentWindow` \| `terminal` | `ask` | Default action when opening a workspace |
 | `git-work-grove.workspaceFile.include` | `string[]` | `["*.code-workspace"]` | Glob patterns for workspace file scanning |
 | `git-work-grove.workspaceFile.exclude` | `string[]` | `[]` | Glob patterns to exclude from scanning |
+| `git-work-grove.customCommands.directory` | `array` | `[]` | Custom commands for repository/worktree items |
+| `git-work-grove.customCommands.workspace` | `array` | `[]` | Custom commands for workspace file items |
 | `git-work-grove.template.*` | `string` | *(varies)* | Display templates (label, description, terminalName) — see [Template Customization](https://github.com/vp-tw/vscode-extension-git-work-grove/blob/main/docs/templates.md) |
 | `git-work-grove.favorites` | `string[]` | `[]` | Ordered list of favorited item paths (managed via the UI) |
 
+### Custom Commands
+
+Define custom commands that appear in the tree view context menu. Two settings are available — one for directory items (repository/worktree), one for workspace file items:
+
+```json
+{
+  "git-work-grove.customCommands.directory": [
+    {
+      "command": ["npm", "run", "dev"],
+      "env": { "NODE_ENV": "development" },
+      "label": "Run Dev Server"
+    }
+  ],
+  "git-work-grove.customCommands.workspace": [
+    {
+      "command": ["code", "--goto", "{path}"],
+      "label": "Open in Terminal"
+    }
+  ]
+}
+```
+
+Each entry has a `label` (shown in QuickPick), a `command` array (`[bin, ...args]`), and an optional `env` object. Both `command` and `env` values support template variables (`{name}`, `{branch}`, `{ref}`, `{head}`, `{path}` — workspace items also have `{dir}` and `{worktree}`).
+
 ### Template Customization
 
 All tree item labels and descriptions are customizable. Templates support variables like `{name}`, `{branch}`, `{ref}`, fallback syntax (`{branch|detached}`), and conditional sections (`{?branch}({branch}){/branch}`).
@@ -145,6 +173,7 @@ These commands appear when right-clicking items in the tree view:
 | Open in Current Window | Open in the current VS Code window |
 | Open in Terminal | Open a terminal at the item's location |
 | Reveal in Finder | Open the item's location in your OS file manager |
+| Custom Commands... | Run a user-defined command (when configured) |
 | Copy Name | Copy the item's display name to clipboard |
 | Copy Path | Copy the item's filesystem path to clipboard |
 | Add Favorite | Pin this item to the Favorites section |
@@ -168,6 +197,7 @@ Design documents for contributors and AI-assisted development:
 - [Open Behavior](https://github.com/vp-tw/vscode-extension-git-work-grove/blob/main/docs/spec/open-behavior.md) — Open modes, URI resolution, click handling
 - [Open in Terminal](https://github.com/vp-tw/vscode-extension-git-work-grove/blob/main/docs/spec/open-in-terminal.md) — CWD resolution, terminal naming, prunable guard
 - [Empty States](https://github.com/vp-tw/vscode-extension-git-work-grove/blob/main/docs/spec/empty-states.md) — Git unavailable, no repository, no worktrees messages
+- [Custom Commands](https://github.com/vp-tw/vscode-extension-git-work-grove/blob/main/docs/spec/custom-commands.md) — Custom commands: settings, execution, context menu
 
 ## Installation