feat(run,notifications,profiles): stop sending prompts nobody typed, and fix notification + profile delivery

Run console:
- Picking a pipeline no longer pre-writes anything into the prompt box
  (`promptPrefill` in `LaneConsolePane.tsx` is gone — it wrote the driving
  slash command on a claude lane and a stage checklist on a codex one).
  Whatever sits in that box is sent as a real prompt the moment the run
  starts, so the box is the user's alone now.
- Resuming a session sends NO prompt at all (`handleStart` in `RunSetup.tsx`):
  the resumed session carries its own transcript, and leftover text in the box
  fired an extra turn into it.

Notifications:
- `client/src/lib/notify.ts` is now the ONE sender, used by both
  `useNotifications` and Settings' test button, and it reports where the
  notification landed: `POST /api/push/send` answering `{native:false,pushed:0}`
  means it went NOWHERE, so the client falls back to a local notification
  instead of counting the 200 as delivered.
- A notification carries the lane that raised it (`/workspace?lane=<id>`), and
  Workspace selects that lane on arrival.

Profiles:
- `server/lib/cc-profiles.js` reads and writes the macOS login Keychain item
  `Claude Code-credentials`, where the `claude` CLI actually keeps
  `claudeAiOauth` on darwin — a switch used to rewrite a file nothing reads.
  The file stays the fallback, is kept in step only when it already exists, and
  `AGENTHUB_CC_KEYCHAIN=0` pins it (tests set it).

Tests: npm run test:server (1820 pass), client vitest (553 pass).

server/README.md

@@ -583,10 +583,9 @@ journal's mtime, under the guard hook ingestion uses (no `run_id`, only from
 
 Getting a codex lane's *declared* stage to actually happen is a separate
 problem — only the session itself can call `agenthub stage`, and unlike a Claude
-lane it has no slash command to pre-fill. `LaneConsolePane.tsx` pre-fills a
-codex pane's opening prompt with a plain-text checklist instead, one
-`agenthub stage <stage> --tool codex` line per node of the lane's own
-`pipeline_nodes`. As a safety net beyond that opening nudge,
+lane it has no slash command to pre-fill — and the run console pre-fills
+nothing into the prompt box any more, for either tool, since anything sitting
+there is sent as a real prompt on start. What is left is
 `server/lib/codex-nudge.js`'s `sweepCodexNudges()` runs on an unref'd 60s
 interval (`DASHBOARD_CODEX_NUDGE_MS`, `0` disables): when a codex lane's fresh
 `detected_stage` has sat ahead of its declared `stage` for at least two