feat(CUB-19): implement AgentStatus SignalR hub for real-time updates

- Add AgentStatusHub with typed IAgentStatusClient interface
  - Hub at /hubs/agent-status (matches design spec)
  - Fleet group + per-agent group subscription
  - AgentStatusChanged and AgentTaskProgress push events
  - Extension methods for server-side push via IHubContext

- Add GatewayEventBridgeService background service
  - Connects to OpenClaw Gateway WebSocket (v3 protocol)
  - Handles challenge → connect → hello-ok handshake
  - Bridges sessions.changed, session.message, session.tool events
  - Translates Gateway session status to AgentStatus enum
  - Maintains in-memory fleet state for snapshot queries

- Add REST API controllers
  - GET /api/agents — fleet status snapshot
  - GET /api/agents/{agentId} — single agent status
  - GET /api/logs/{agentId} — agent session logs (stub)
  - POST /api/command/stop/{agentId} — stop agent
  - POST /api/command/restart/{agentId} — restart agent
  - POST /api/command/steer/{agentId} — inject message

- Add models matching TypeScript spec interfaces
  - AgentStatusUpdate, TaskProgressUpdate, AgentCardData
  - AgentStatus enum (active/idle/thinking/error)

- Configure CORS with credentials for SignalR WebSocket
- Configure Swagger/OpenAPI with XML doc comments
- Agent role map matching frontend AGENT_ROLES constant

backend/ControlCenter/obj/Debug/net9.0/ControlCenter.GeneratedMSBuildEditorConfig.editorconfig

@@ -0,0 +1,21 @@
+is_global = true
+build_property.TargetFramework = net9.0
+build_property.TargetPlatformMinVersion = 
+build_property.UsingMicrosoftNETSdkWeb = true
+build_property.ProjectTypeGuids = 
+build_property.InvariantGlobalization = 
+build_property.PlatformNeutralAssembly = 
+build_property.EnforceExtendedAnalyzerRules = 
+build_property._SupportedPlatformList = Linux,macOS,Windows
+build_property.RootNamespace = ControlCenter
+build_property.RootNamespace = ControlCenter
+build_property.ProjectDir = /home/overseer/projects/control-center/backend/ControlCenter/
+build_property.EnableComHosting = 
+build_property.EnableGeneratedComInterfaceComImportInterop = 
+build_property.RazorLangVersion = 9.0
+build_property.SupportLocalizedComponentNames = 
+build_property.GenerateRazorMetadataSourceChecksumAttributes = 
+build_property.MSBuildProjectDirectory = /home/overseer/projects/control-center/backend/ControlCenter
+build_property._RazorSourceGeneratorDebug = 
+build_property.EffectiveAnalysisLevelStyle = 9.0
+build_property.EnableCodeStyleSeverity =