Workspace isolation for concurrent tasks (git worktrees)

[kovtcharov-amd]

Problem

When multiple Claude Code tasks run in the same workspace, they share a single git working tree. This causes:

• Race conditions on file edits — two tasks modifying the same file overwrite each other
• Git state conflicts — Task A commits while Task B has uncommitted changes, blocking B's commit
• No branch isolation — all tasks operate on the same branch with the same staging area

Traditional file locking (e.g., flock, LockFileEx) is not a viable solution because:

• Git operations are atomic across many files — you can't lock "a commit"
• Cross-file dependencies create deadlock risk
• Cross-process file locking is fragile and platform-inconsistent

Proposed Solution

Use git worktrees to give each task (or group of tasks) its own isolated working directory and branch.

Detailed design: docs/plans/git-worktree-support.md

Note: The plan document needs to be committed to main for the link above to resolve.

Scope

Priority	Item	Description
P0	WorktreeManager backend module	list, create, remove, prune wrapping git worktree commands
P0	REST/WS endpoints for worktree CRUD	Query-param based (/api/worktrees?workspace=...)
P1	Auto-worktree mode	Per-workspace toggle: new tasks auto-create an isolated worktree
P1	Sidebar UX	Worktree workspaces grouped under parent, branch icon, count badge
P2	Worktree management panel	List, remove, prune stale worktrees
P2	MCP isolate parameter	Let orchestrator agents request worktree isolation via claudia_create_task
P3	Warning for concurrent tasks without isolation	Toast when 2+ tasks run in the same workspace without worktrees

What already exists

• Atomic writes for Claudia internal files (tasks.json, config.json)
• Mtime-based detection of multiple server instances
• Detailed design doc (linked above)

Key edge cases to handle

• Windows path encoding in REST URLs (use query params, not path params)
• .git/info/exclude instead of modifying tracked .gitignore
• Submodule initialization in new worktrees
• Stale worktree cleanup when directories are deleted externally
• Block parent workspace removal if worktree children exist