perf(projects): lazy-load TaskMaster metadata per selected project

Why:

- /api/projects is a hot path (initial load, sidebar refresh, websocket sync).

- Scanning .taskmaster for every project on each call added avoidable fs I/O and payload size.

- TaskMaster metadata is only needed after selecting a specific project.

- Moving it to a project-scoped endpoint makes loading cost match user intent.

- The UI now hydrates TaskMaster state on selection and keeps it across refresh events.

- This prevents status flicker/regression while still removing global scan overhead.

- Selection fetches are sequence-guarded to block stale async responses on fast switching.

- isManuallyAdded was removed from responses to keep the public project contract minimal.

- Project dumps now use incrementing snapshot files to preserve history for debugging.

What changed:

- Added GET /api/projects/:projectName/taskmaster and getProjectTaskMaster().

- Removed TaskMaster detection from bulk getProjects().

- Added api.projectTaskmaster(...) plus selection-time hydration in frontend contexts.

- Merged cached taskmaster values into refreshed project lists for continuity.

- Removed isManuallyAdded from manual project payloads.

src/utils/api.js

@@ -52,6 +52,8 @@ export const api = {
   // Protected endpoints
   // config endpoint removed - no longer needed (frontend uses window.location)
   projects: () => authenticatedFetch('/api/projects'),
+  projectTaskmaster: (projectName) =>
+    authenticatedFetch(`/api/projects/${encodeURIComponent(projectName)}/taskmaster`),
   sessions: (projectName, limit = 5, offset = 0) =>
     authenticatedFetch(`/api/projects/${projectName}/sessions?limit=${limit}&offset=${offset}`),
   // Unified endpoint — all providers through one URL