The runtime_brief_slim feature flag has burned in; the slim runtime brief is now the sole path.
- execenv: buildMetaSkillContent / BuildCommentReplyInstructions delegate to the slim assembler unconditionally; delete the legacy verbose brief body and writeBackgroundTaskSafetyInstructions.
- Remove the runtime_brief_slim flag and the daemon-bound flag delivery subsystem built solely for it: execenv flag wiring (runtime_config_flag.go, server_snapshot_provider.go), the featureflagdispatch package, the DaemonFeatureFlagSnapshot heartbeat protocol field, and the server/daemon wiring in router.go, handler, daemon.go, main.go, cmd_daemon.go.
- Keep the generic server/pkg/featureflag engine (still used by composio_mcp_apps).
- Update tests to slim-only expectations and docs/feature-flags.md.
Co-authored-by: multica-agent <github@multica.ai>