fix(gui): CI activation order + review-bot findings

The session-title snapshot exposed a real activation race: ui-trajectory
and ui-question register into conversation-declared slots but only
injected 'slots', so nothing ordered their applies after ui-conversation's
— register() into the undeclared slot threw and the entry FAILED. Both now
inject 'conversation' as an ordering edge (documented as such; specs stub
the service where the bench declares the slot itself).

Review-bot findings, all three applied: the module loader's load sink
cross-checks the handoff id against the arriving row (a mis-stamped bundle
can no longer register under another entry's identity); the default
execute seam removes the inline script node right after its synchronous
execution (repeated HMR rebuilds no longer accumulate dead nodes); a
throwing onRebuilt subscriber is contained per-listener and routed to
onError instead of escaping the fs.watchFile callback.

packages/host/webserver/src/web-plugins.ts

@@ -247,7 +247,15 @@ export function createHostWebPluginRegistry(deps: WebPluginRegistryDeps): HostWe
           return
         }
         if (rev === undefined || rev === before) return
-        for (const notify of rebuildListeners) notify(id, rev)
+        for (const notify of rebuildListeners) {
+          // A throwing subscriber must not escape the fs.watchFile callback
+          // (that would skip later subscribers and can kill the process).
+          try {
+            notify(id, rev)
+          } catch (error) {
+            deps.onError(error instanceof Error ? error : new Error(String(error)))
+          }
+        }
       }
       watchFile(record.clientPath, { interval: watchInterval, persistent: false }, listener)
       watched.set(id, { path: record.clientPath, listener })