[Feature Request] Add configurable worktree base path with template support

Bug Description
EnterWorktree currently hardcodes new worktrees to <repo>/.claude/worktrees/<name>. Many users (and tools like git-worktree-runner / git gtr) use a sibling-folder convention — {reporoot}-worktrees/<name>/ — to keep worktrees out of the repo tree, avoid .gitignore clutter, and group all branches of a repo at the same filesystem level.

The current worktree settings only expose symlinkDirectories, sparsePaths, and baseRef. There's no way to redirect the create-path.

Request: add a worktree.basePath (or similar) setting that accepts:

• An absolute path, OR
• A template with {repoRoot} / {repoName} placeholders so a single user-level setting works across all repos. e.g. "{repoRoot}-worktrees" resolves to /Users/me/src/foo-worktrees/ for any repo at /Users/me/src/foo/.

Workaround today: create the worktree externally (git gtr new <name> or git worktree add) and then have Claude join it via EnterWorktree(path: ...). Functional but requires the user to set up the worktree themselves — defeats the convenience of /enter-worktree.

Bonus: if implemented, also respect git gtr's configured base path via .gtrconfig auto-detection, so users of that tool get the right behavior with zero settings.

Environment Info

• Platform: darwin
• Terminal: tmux
• Version: 2.1.142
• Feedback ID: a9c869d4-d41d-455c-85ad-a18c736519b7

Errors

[{"error":"Error: ECONNREFUSED\n    at from (/$bunfs/root/src/entrypoints/cli.js:118:7862)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:126:12906)\n    at emitError (node:events:43:23)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:125:1149)\n    at emitError (node:events:43:23)\n    at <anonymous> (node:_http_client:251:22)\n    at processTicksAndRejections (native:7:39)\n    at request (/$bunfs/root/src/entrypoints/cli.js:128:2467)\n    at async s7_ (/$bunfs/root/src/entrypoints/cli.js:252:277804)\n    at async A68 (/$bunfs/root/src/entrypoints/cli.js:408:5977)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-06-01T14:33:01.438Z"},{"error":"Error: ECONNREFUSED\n    at from (/$bunfs/root/src/entrypoints/cli.js:118:7862)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:126:12906)\n    at emitError (node:events:43:23)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:125:1149)\n    at emitError (node:events:43:23)\n    at <anonymous> (node:_http_client:251:22)\n    at processTicksAndRejections (native:7:39)\n    at request (/$bunfs/root/src/entrypoints/cli.js:128:2467)\n    at async s7_ (/$bunfs/root/src/entrypoints/cli.js:252:277804)\n    at async A68 (/$bunfs/root/src/entrypoints/cli.js:408:5977)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-06-01T14:37:06.428Z"},{"error":"Error: Was there a typo in the url or port?\n    at from (/$bunfs/root/src/entrypoints/cli.js:118:7862)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:126:12906)\n    at emitError (node:events:43:23)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:125:1149)\n    at emitError (node:events:43:23)\n    at <anonymous> (node:_http_client:251:22)\n    at processTicksAndRejections (native:7:39)\n    at request (/$bunfs/root/src/entrypoints/cli.js:128:2467)\n    at async s7_ (/$bunfs/root/src/entrypoints/cli.js:252:277804)\n    at async A68 (/$bunfs/root/src/entrypoints/cli.js:408:5977)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-06-01T14:37:15.099Z"},{"error":"Error: ECONNREFUSED\n    at from (/$bunfs/root/src/entrypoints/cli.js:118:7862)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:126:12906)\n    at emitError (node:events:43:23)\n    at <anonymous> (/$bunfs/root/src/entrypoints/cli.js:125:1149)\n    at emitError (node:events:43:23)\n    at <anonymous> (node:_http_client:251:22)\n    at processTicksAndRejections (native:7:39)\n    at request (/$bunfs/root/src/entrypoints/cli.js:128:2467)\n    at async s7_ (/$bunfs/root/src/entrypoints/cli.js:252:277804)\n    at async A68 (/$bunfs/root/src/entrypoints/cli.js:408:5977)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-06-01T14:37:16.154Z"}]