feat: Read My Mind phase 1, per-case intent profiles (capture + API + skill)

Per-case profiles of user intent (docs/readmymind-plan.md): user-stated goals
plus the user's recently submitted prompts, captured from the Claude session
transcript behind the new synced readMyMindEnabled setting (default OFF).

- intent-store.ts: keyed by owner + realpath(workingDir), FIFO/size caps,
  consecutive-dupe collapse, atomic 0600 writes to ~/.codeman/intents.json
- transcript-watcher.ts: new transcript:user_prompt event for typed user turns
  (tool_result-only entries stay silent); capture wiring in server.ts is
  claude-only and gated on the setting per event
- readmymind-routes.ts: GET/PUT/DELETE /api/sessions/:id/intent, ownership
  via findSessionOrFail, strict Zod schema
- agent skill: SKILL.md recipe + endpoints.md rows so agents can read and
  record intent (PUT replaces: read + merge; never delete unprompted)
- groundwork for the phase-2 predictor button; nothing is ever auto-sent

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/types/index.ts

@@ -71,3 +71,4 @@ export * from './workflow-run.js';
 export * from './search.js';
 export * from './user.js';
 export * from './webview.js';
+export * from './intent.js';