feat: config & onboarding — each teammate connects their own Gitea (Phase A)

The foundation for a shareable team build. Replaces the .env.local-only dev config
with a real, per-teammate connection flow.

main:
- config-store.ts: token encrypted at rest via Electron safeStorage (OS keychain),
  config JSON in userData. Token lives only in main; renderer gets everything but.
- resolveConfig: saved config > .env.local (dev) > null; ignored under COMMITEA_E2E.
  pm-state repo defaults to `${repo}-pm-state`. resetClients() re-reads on change so
  saving config takes effect without a restart. gitea:status gains `demo` (e2e).
- IPC: config:get (no token), config:test (authed read validates token+repo),
  config:set (encrypt+save+reset), config:clear. Model bridge reads config.modelUrl
  and probes reachability — chat is "configured" only if a model actually answers;
  localhost default is dev-only (app.isPackaged gate).

renderer:
- ConnectScreen: real onboarding form (URL/owner/repo/PAT/optional model) → test →
  save. AppShell gates on it: demo → shell (fixtures/e2e); configured → shell (real);
  else → connect. Settings Connection card is real (repo/url/model/sidecar) with
  Reconfigure + Disconnect. Chat cleanly disables with a "no model" state instead of
  the scripted canned reply.

Verified: main + desktop typecheck clean, 14 fixture e2e green (demo mode unchanged),
live onboarding e2e: fresh app → connect form → validated PAT → real board (24 done /
10 open). COMMITEA_NO_ENV_LOCAL + COMMITEA_USERDATA are test hooks for the onboarding path.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

apps/desktop/src/preload/index.ts

@@ -22,6 +22,16 @@ const api = {
     /** Read the capacity config from the pm-state repo. */
     capacity: () => ipcRenderer.invoke('pmstate:capacity'),
   },
+  config: {
+    /** The saved config (never the token) — null when unset. */
+    get: () => ipcRenderer.invoke('config:get'),
+    /** Validate a token + repo before saving. */
+    test: (cfg: unknown) => ipcRenderer.invoke('config:test', cfg),
+    /** Save config (token encrypted in main); takes effect without restart. */
+    set: (cfg: unknown) => ipcRenderer.invoke('config:set', cfg),
+    /** Forget the saved config. */
+    clear: () => ipcRenderer.invoke('config:clear'),
+  },
   model: {
     /** Whether a model endpoint is configured (else the UI keeps the scripted Reginald). */
     status: () => ipcRenderer.invoke('model:status'),