poc-daemon: fix idle nudge and notification delivery

- Strip context bloat from nudge messages — no more IRC digest, git
  log, or work state inlined into tmux send-keys (was silently dropping
  the entire message). Nudge now just includes pending notification count.
- Notifications no longer send directly via tmux — they flow through
  the idle nudge only. Urgent notifications reset the fired flag so
  the nudge fires sooner.
- Add test-nudge RPC that exercises the actual daemon send path
  (test-send was client-side only, didn't test the real code path).
- Update nudge text: "Let your feelings guide your thinking."
- Increase send-keys sleep from 200ms to 500ms.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

poc-daemon/schema/daemon.capnp

@@ -76,6 +76,8 @@ interface Daemon {
   afk              @21 () -> ();
   sessionTimeout   @22 (seconds :Float64) -> ();
 
+  testNudge        @23 () -> (sent :Bool, message :Text);
+
   # Modules
   moduleCommand    @15 (module :Text, command :Text, args :List(Text))
                        -> (result :Text);