feat: Replace capability broadcasting with availability broadcasting

- Add availability broadcasting every 30s showing real working status
- Replace constant capability broadcasts with change-based system
- Implement persistent capability storage in ~/.config/bzzz/
- Add SimpleTaskTracker for real task status monitoring
- Only broadcast capabilities on startup or when models/capabilities change
- Add proper Hive API URL configuration and integration
- Fix capability change detection with proper comparison logic

This eliminates P2P mesh spam and provides accurate node availability.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

test-config.yaml

@@ -0,0 +1,21 @@
+hive_api:
+  base_url: "https://hive.home.deepblack.cloud"
+  api_key: ""
+  timeout: "30s"
+
+agent:
+  id: "test-agent"
+  capabilities: ["task-coordination", "meta-discussion", "general"]
+  models: ["phi3"]
+  specialization: "general_developer"
+  poll_interval: "60s"
+  max_tasks: 1
+
+github:
+  token_file: ""
+
+p2p:
+  escalation_webhook: "https://n8n.home.deepblack.cloud/webhook-test/human-escalation"
+
+logging:
+  level: "debug"