feat(desktop): isolate development profiles per worktree

[chihumyum]

Summary

Multiple development checkouts currently share the default data directory. A branch that writes a different persisted format can leave another checkout unable to start its Runtime Host.

Add npm run dev:worktree to select a separate, stable profile from the checkout's canonical path. The command prints the selected directory and reuses the existing HMR launcher. Explicit --user-data-dir arguments take precedence. The default npm run dev behavior is unchanged; profiles start empty, and existing data is neither copied nor removed.

Includes platform-specific profile locations, argument validation, and English/Chinese contributor documentation. Profile identity follows the checkout path, so switching branches within one checkout reuses its data.

Verification

• 26 launcher tests pass, including profile separation, stable paths, symlink aliases, platform locations, explicit overrides, invalid arguments, and plain/TCC argument forwarding.
• npm run lint, npm run format:check, npm run build, npm run typecheck, and npm run check:asf-headers pass.
• npx knip --workspace apps/desktop, npx knip --workspace packages/ui, and git diff --check pass.
• macOS smoke: npm run dev:worktree printed a directory under ~/Library/Application Support/Maka Dev Worktrees/, launched on Vite port 5174 alongside an existing development instance, and displayed onboarding. Stopping this launcher left the existing instance running.
• Windows/Linux path selection and TCC forwarding are covered by tests; Windows/Linux launches and a TCC permission-grant flow were not run. The full workspace test suite was not run locally.

AI use

• No generative tool made a substantive contribution
• Generative tooling made a substantive contribution

Tool(s) and scope: Codex implemented the launcher, tests, and documentation, ran the checks, and prepared this pull request. The commit includes Generated-by: Codex.

Checklist

• Tests cover the change and fail without it
• Lint, format, typecheck and the affected suites pass locally

Does this PR entail a change in behavior?

• Yes — described under Summary above
• No