CUB-123: integrate gateway, wire PostgreSQL repositories, add SSE streaming

- Create repository/ package with pgx-backed CRUD for agents, sessions, tasks, projects
- Define AgentRepo/SessionRepo/TaskRepo/ProjectRepo interfaces
- Update handler to use repository interfaces instead of in-memory stores
- Add SSE broker with GET /api/events endpoint (text/event-stream)
- Add gateway client that polls OpenClaw for agent states
- Add GATEWAY_URL and GATEWAY_POLL_INTERVAL config fields
- Seed 5 demo agents (Otto, Rex, Dex, Hex, Pip) on empty DB
- Update router to wire SSE broker
- All 21 handler tests pass with mock repos

go-backend/internal/router/router.go

@@ -3,6 +3,7 @@
 package router
 
 import (
+	"context"
 	"net/http"
 	"time"
 
@@ -13,11 +14,13 @@ import (
 	"github.com/go-chi/cors"
 )
 
-// Dependencies carries the handler and database pool into the router.
+// Dependencies carries the handler, database pool, SSE broker, and CORS
+// configuration into the router.
 type Dependencies struct {
-	Handler   *handler.Handler
-	DB        *db.Pool
+	Handler    *handler.Handler
+	Pool       *db.Pool
 	CORSOrigin string
+	Broker     *handler.Broker
 }
 
 // New creates a fully-configured chi router with all API routes mounted.
@@ -49,8 +52,10 @@ func New(deps *Dependencies) *chi.Mux {
 	r.Get("/health", func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/json")
 		status := "ok"
-		if deps.DB != nil {
-			if err := deps.DB.Health(r.Context()); err != nil {
+		if deps.Pool != nil {
+			ctx, cancel := context.WithTimeout(r.Context(), 3*time.Second)
+			defer cancel()
+			if err := deps.Pool.Ping(ctx); err != nil {
 				w.WriteHeader(http.StatusServiceUnavailable)
 				status = "db_unhealthy"
 			}
@@ -62,11 +67,11 @@ func New(deps *Dependencies) *chi.Mux {
 	r.Route("/api", func(api chi.Router) {
 		// Agents CRUD
 		api.Route("/agents", func(agents chi.Router) {
-			agents.Get("/", deps.Handler.ListAgents)       // GET /api/agents
-			agents.Post("/", deps.Handler.CreateAgent)      // POST /api/agents
-			agents.Get("/{id}", deps.Handler.GetAgent)       // GET /api/agents/{id}
-			agents.Put("/{id}", deps.Handler.UpdateAgent)    // PUT /api/agents/{id}
-			agents.Delete("/{id}", deps.Handler.DeleteAgent) // DELETE /api/agents/{id}
+			agents.Get("/", deps.Handler.ListAgents)            // GET /api/agents
+			agents.Post("/", deps.Handler.CreateAgent)           // POST /api/agents
+			agents.Get("/{id}", deps.Handler.GetAgent)            // GET /api/agents/{id}
+			agents.Put("/{id}", deps.Handler.UpdateAgent)         // PUT /api/agents/{id}
+			agents.Delete("/{id}", deps.Handler.DeleteAgent)      // DELETE /api/agents/{id}
 			agents.Get("/{id}/history", deps.Handler.AgentHistory) // GET /api/agents/{id}/history
 		})
 
@@ -78,6 +83,9 @@ func New(deps *Dependencies) *chi.Mux {
 
 		// Projects
 		api.Get("/projects", deps.Handler.ListProjects)
+
+		// SSE event stream
+		api.Get("/events", deps.Broker.ServeHTTP)
 	})
 
 	return r