Adds @spec annotations to all public functions in agent-related modules for
better static analysis and documentation.
Changes:
- Added 17 typespecs to Towerops.Agents context module
- All CRUD operations (create, read, update, delete, revoke)
- Assignment management functions
- Agent token resolution and lookup functions
- PubSub broadcast function
- Added 9 typespecs to Towerops.Agents.Stats module
- Agent health and metrics statistics
- Device assignment breakdowns
- Latency analysis and reassignment candidate detection
- Added typespec to Towerops.Workers.StaleAgentWorker
- find_stale_agents/0 function
- Preserved existing typespecs in AgentChannel (socket types)
Benefits:
- Improved code documentation with clear function signatures
- Better static analysis via dialyzer
- Clearer API contracts for all agent management functions
- Type-safe UUID handling throughout agent system