feat(server): wire PgEventBus and event-driven settings cache into process assembly

main.ts starts the PG-backed SSE bus (api/worker processes now see each other's events)
and stops it on shutdown; bootstrap passes ctx.events to the settings reader so
settings.changed invalidates every process's cache.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

apps/server/src/context.ts

@@ -147,7 +147,7 @@ export async function bootstrap(opts: BootstrapOptions): Promise<Bootstrapped> {
     engine,
     outbox,
     secrets: createSecretStore({ db, masterKey: config.SECRET_MASTER_KEY }),
-    settings: createSettingsReader({ db, logger }),
+    settings: createSettingsReader({ db, logger, events: opts.events }),
     capabilities: createCapabilityRegistry({ logger }),
   };
   const tasks = buildTaskRegistry(opts.modules, ctx);