Add startup summary for active profile, routers, and bootstraps

- Add BootstrapResult dataclass for structured bootstrap results
- bootstrap_linguistic_models() and bootstrap_local_llm_models() return BootstrapResult
- Set ALWRITY_ACTIVE_PROFILE env var at startup and print active profile
- Set ALWRITY_BOOTSTRAP_SUMMARY with JSON summary of bootstrap results
- Print bootstrap summary at startup
- Track skipped_routers in RouterManager with reasons
- Add log_startup_summary() to log enabled/skipped/failed routers
- Call log_startup_summary() in app.py after router inclusion

backend/app.py

@@ -328,6 +328,9 @@ else:
         "reason": "Full mode",
     }
 
+# Log startup summary
+router_manager.log_startup_summary()
+
 # Safety net: keep subscription routes available even if core inclusion flow changes
 # in special modes (e.g., demo mode). De-dup is handled by RouterManager.
 router_manager.include_router_safely(subscription_router, "subscription")