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/gateway/client.go

@@ -0,0 +1,198 @@
+// Package gateway provides an OpenClaw gateway integration client that
+// polls agent states, persists them via the repository layer, and broadcasts
+// changes through the SSE broker for real-time frontend updates.
+package gateway
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"net/http"
+	"time"
+
+	"code.cubecraftcreations.com/CubeCraft-Creations/Control-Center/go-backend/internal/handler"
+	"code.cubecraftcreations.com/CubeCraft-Creations/Control-Center/go-backend/internal/models"
+	"code.cubecraftcreations.com/CubeCraft-Creations/Control-Center/go-backend/internal/repository"
+)
+
+// Client polls the OpenClaw gateway for agent status and keeps the database
+// and SSE broker in sync.
+type Client struct {
+	url          string
+	pollInterval time.Duration
+	httpClient   *http.Client
+	agents       repository.AgentRepo
+	broker       *handler.Broker
+}
+
+// Config holds gateway client configuration, typically loaded from environment.
+type Config struct {
+	URL          string
+	PollInterval time.Duration
+}
+
+// DefaultConfig returns sensible defaults for local development.
+func DefaultConfig() Config {
+	return Config{
+		URL:          "http://localhost:18789/api/agents",
+		PollInterval: 5 * time.Second,
+	}
+}
+
+// NewClient returns a gateway client wired to the given repository and broker.
+func NewClient(cfg Config, agents repository.AgentRepo, broker *handler.Broker) *Client {
+	return &Client{
+		url:          cfg.URL,
+		pollInterval: cfg.PollInterval,
+		httpClient:   &http.Client{Timeout: 10 * time.Second},
+		agents:       agents,
+		broker:       broker,
+	}
+}
+
+// Start begins the polling loop. It runs until ctx is cancelled.
+func (c *Client) Start(ctx context.Context) {
+	slog.Info("gateway client starting",
+		"url", c.url,
+		"pollInterval", c.pollInterval.String())
+
+	ticker := time.NewTicker(c.pollInterval)
+	defer ticker.Stop()
+
+	for {
+		select {
+		case <-ctx.Done():
+			slog.Info("gateway client stopped")
+			return
+		case <-ticker.C:
+			c.poll(ctx)
+		}
+	}
+}
+
+// poll fetches agent states from the gateway and syncs to the database.
+func (c *Client) poll(ctx context.Context) {
+	resp, err := c.httpClient.Get(c.url)
+	if err != nil {
+		slog.Warn("gateway poll failed", "error", err)
+		return
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		slog.Warn("gateway returned non-200", "status", resp.StatusCode)
+		return
+	}
+
+	var agents []models.AgentCardData
+	if err := json.NewDecoder(resp.Body).Decode(&agents); err != nil {
+		slog.Warn("gateway response parse failed", "error", err)
+		return
+	}
+
+	for _, ga := range agents {
+		// Check if agent already exists; if so, update; otherwise create.
+		existing, err := c.agents.Get(ctx, ga.ID)
+		if err != nil {
+			// Not found — create it
+			if err := c.agents.Create(ctx, ga); err != nil {
+				slog.Warn("gateway agent create failed", "id", ga.ID, "error", err)
+				continue
+			}
+			slog.Info("gateway agent created", "id", ga.ID, "status", ga.Status)
+			c.broker.Broadcast("agent.status", ga)
+			continue
+		}
+
+		// If status changed, update and broadcast
+		if existing.Status != ga.Status {
+			updated, err := c.agents.Update(ctx, ga.ID, models.UpdateAgentRequest{
+				Status: &ga.Status,
+			})
+			if err != nil {
+				slog.Warn("gateway agent update failed", "id", ga.ID, "error", err)
+				continue
+			}
+			c.broker.Broadcast("agent.status", updated)
+			slog.Debug("agent status changed",
+				"id", ga.ID,
+				"from", existing.Status,
+				"to", ga.Status)
+		}
+	}
+}
+
+// SeedDemoAgents inserts the five known demo agents if the agents table is
+// empty. Call this once on application startup after migrations have run.
+func SeedDemoAgents(ctx context.Context, agents repository.AgentRepo) error {
+	count, err := agents.Count(ctx)
+	if err != nil {
+		return fmt.Errorf("count agents for seeding: %w", err)
+	}
+	if count > 0 {
+		return nil // already seeded
+	}
+
+	slog.Info("seeding demo agents")
+	demoAgents := []models.AgentCardData{
+		{
+			ID:           "otto",
+			DisplayName:  "Otto",
+			Role:         "Orchestrator",
+			Status:       models.AgentStatusActive,
+			CurrentTask:  strPtr("Orchestrating tasks"),
+			SessionKey:   "otto-session",
+			Channel:       "discord",
+			LastActivity: time.Now().UTC().Format(time.RFC3339),
+		},
+		{
+			ID:           "rex",
+			DisplayName:  "Rex",
+			Role:         "Frontend Dev",
+			Status:       models.AgentStatusIdle,
+			SessionKey:   "rex-session",
+			Channel:       "discord",
+			LastActivity: time.Now().UTC().Add(-10 * time.Minute).Format(time.RFC3339),
+		},
+		{
+			ID:           "dex",
+			DisplayName:  "Dex",
+			Role:         "Backend Dev",
+			Status:       models.AgentStatusThinking,
+			CurrentTask:  strPtr("Designing API contracts"),
+			SessionKey:   "dex-session",
+			Channel:       "discord",
+			LastActivity: time.Now().UTC().Format(time.RFC3339),
+		},
+		{
+			ID:           "hex",
+			DisplayName:  "Hex",
+			Role:         "Database Specialist",
+			Status:       models.AgentStatusActive,
+			CurrentTask:  strPtr("Reviewing schema migrations"),
+			SessionKey:   "hex-session",
+			Channel:       "discord",
+			LastActivity: time.Now().UTC().Format(time.RFC3339),
+		},
+		{
+			ID:           "pip",
+			DisplayName:  "Pip",
+			Role:         "Edge Device Dev",
+			Status:       models.AgentStatusIdle,
+			SessionKey:   "pip-session",
+			Channel:       "discord",
+			LastActivity: time.Now().UTC().Add(-1 * time.Hour).Format(time.RFC3339),
+		},
+	}
+
+	for _, a := range demoAgents {
+		if err := agents.Create(ctx, a); err != nil {
+			return fmt.Errorf("seed agent %s: %w", a.ID, err)
+		}
+	}
+	slog.Info("demo agents seeded", "count", len(demoAgents))
+	return nil
+}
+
+func strPtr(s string) *string { return &s }