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/repository/project_repository.go

@@ -0,0 +1,94 @@
+package repository
+
+import (
+	"context"
+	"time"
+
+	"code.cubecraftcreations.com/CubeCraft-Creations/Control-Center/go-backend/internal/models"
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+// ProjectRepository provides PostgreSQL-backed CRUD for projects.
+type ProjectRepository struct {
+	pool *pgxpool.Pool
+}
+
+// NewProjectRepository returns a repository wired to the given connection pool.
+func NewProjectRepository(pool *pgxpool.Pool) *ProjectRepository {
+	return &ProjectRepository{pool: pool}
+}
+
+// Create inserts a new project. The current projects table only stores
+// a single agent_id, so we use the first entry from AgentIDs if present.
+func (r *ProjectRepository) Create(ctx context.Context, p models.Project) (models.Project, error) {
+	now := time.Now().UTC()
+	if p.CreatedAt.IsZero() {
+		p.CreatedAt = now
+	}
+	if p.UpdatedAt.IsZero() {
+		p.UpdatedAt = now
+	}
+
+	var agentID *string
+	if len(p.AgentIDs) > 0 {
+		agentID = &p.AgentIDs[0]
+	}
+
+	err := r.pool.QueryRow(ctx, `
+		INSERT INTO projects (name, description, status, agent_id, created_at, updated_at)
+		VALUES ($1, $2, $3, $4, $5, $6)
+		RETURNING id, name, description, status, agent_id, created_at, updated_at
+	`, p.Name, p.Description, string(p.Status), agentID, p.CreatedAt, p.UpdatedAt).Scan(
+		&p.ID, &p.Name, &p.Description, &p.Status, &agentID,
+		&p.CreatedAt, &p.UpdatedAt,
+	)
+	if err != nil {
+		return p, err
+	}
+
+	if agentID != nil {
+		p.AgentIDs = []string{*agentID}
+	} else {
+		p.AgentIDs = []string{}
+	}
+
+	return p, nil
+}
+
+// List returns all projects ordered by name.
+func (r *ProjectRepository) List(ctx context.Context) ([]models.Project, error) {
+	rows, err := r.pool.Query(ctx, `
+		SELECT id, name, description, status, agent_id, created_at, updated_at
+		FROM projects
+		ORDER BY name
+	`)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	return pgx.CollectRows(rows, func(row pgx.CollectableRow) (models.Project, error) {
+		var p models.Project
+		var agentID *string
+
+		if err := row.Scan(&p.ID, &p.Name, &p.Description, &p.Status,
+			&agentID, &p.CreatedAt, &p.UpdatedAt); err != nil {
+			return p, err
+		}
+
+		if agentID != nil {
+			p.AgentIDs = []string{*agentID}
+		} else {
+			p.AgentIDs = []string{}
+		}
+		return p, nil
+	})
+}
+
+// Count returns the total number of projects.
+func (r *ProjectRepository) Count(ctx context.Context) (int, error) {
+	var n int
+	err := r.pool.QueryRow(ctx, `SELECT COUNT(*) FROM projects`).Scan(&n)
+	return n, err
+}