feat: parliament seat collaboration loop (0.9.19)

Seats publish via parliament_note, sync pushes on write, member join without
stealing the chair, and worker tools are hard-gated when parliament is active.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/parliament_daemon.c

@@ -281,7 +281,9 @@ int cst_parliament_daemon_run(const char *password, const char *instance_id,
       sync_on_session(&sess);
       cst_peer_close(&sess);
     }
-    if (++tick % 10 == 0 && disc) {
+    int push = cst_parliament_sync_pending();
+    tick++;
+    if ((push || tick % 10 == 0) && disc) {
       cst_peer_info_t peers[16];
       int n = cst_discover_peers(disc, peers, 16);
       for (int i = 0; i < n; i++) {
@@ -293,6 +295,8 @@ int cst_parliament_daemon_run(const char *password, const char *instance_id,
           cst_peer_close(&sess);
         }
       }
+      if (push)
+        cst_parliament_sync_ack();
     }
     sleep_ms(200);
   }