097d7dc547
Three coupled gaps surfaced after the initial spawn fix: 1. fallback-retry-handler dropped task.skillContent and task.sessionPermission when rebuilding LaunchInput, so the retried background task lost the delegated system prompt and question-deny permission rule. 2. manager.startTask never bound the child sessionID to the resolved agent via setSessionAgent, leaving runtime fallback and other hooks with no idea which agent owned the new child session. 3. The fallback-to-general path in spawner.ts rebuilt the prompt body without going through buildFallbackBody, so bootstrap state, session tools, and session agent updates drifted apart. Persist skillContent and sessionPermission on BackgroundTask, bind setSessionAgent/updateSessionAgent at session creation and on fallback, and route the FALLBACK_AGENT retry through buildFallbackBody so the prompt body, bootstrap tools, and session registries all agree.