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/agent_repository.go

@@ -0,0 +1,186 @@
+// Package repository provides PostgreSQL-backed CRUD implementations
+// for the Control Center domain entities. Each repository takes a
+// *pgxpool.Pool in its constructor and uses pgx.CollectRows() for scanning.
+package repository
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"code.cubecraftcreations.com/CubeCraft-Creations/Control-Center/go-backend/internal/models"
+	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgxpool"
+)
+
+// AgentRepository provides PostgreSQL-backed CRUD for agents.
+type AgentRepository struct {
+	pool *pgxpool.Pool
+}
+
+// NewAgentRepository returns a repository wired to the given connection pool.
+func NewAgentRepository(pool *pgxpool.Pool) *AgentRepository {
+	return &AgentRepository{pool: pool}
+}
+
+// Create inserts a new agent. It maps the models.AgentCardData fields onto
+// the agents table columns (uuid id, text name, text status, text task,
+// int progress, text session_key, text channel).
+func (r *AgentRepository) Create(ctx context.Context, a models.AgentCardData) error {
+	prog := 0
+	if a.TaskProgress != nil {
+		prog = *a.TaskProgress
+	}
+
+	_, err := r.pool.Exec(ctx, `
+		INSERT INTO agents (id, name, status, task, progress, session_key, channel, last_activity)
+		VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
+	`, a.ID, a.DisplayName, string(a.Status), a.CurrentTask, prog,
+		a.SessionKey, a.Channel, time.Now().UTC())
+
+	return err
+}
+
+// Get returns a single agent by its string id.
+func (r *AgentRepository) Get(ctx context.Context, id string) (models.AgentCardData, error) {
+	var a models.AgentCardData
+	var task *string
+	var prog int
+	var lastActivity time.Time
+
+	err := r.pool.QueryRow(ctx, `
+		SELECT id, name, status, task, progress, session_key, channel, last_activity
+		FROM agents WHERE id = $1
+	`, id).Scan(&a.ID, &a.DisplayName, &a.Status, &task, &prog,
+		&a.SessionKey, &a.Channel, &lastActivity)
+
+	if err != nil {
+		return a, err
+	}
+
+	a.CurrentTask = task
+	if prog > 0 || task != nil {
+		p := prog
+		a.TaskProgress = &p
+	}
+	a.LastActivity = lastActivity.UTC().Format(time.RFC3339)
+
+	// Role is not persisted in the current schema — set a sensible default.
+	a.Role = "agent"
+
+	return a, nil
+}
+
+// List returns all agents, optionally filtered by status.
+// Results are ordered by name (display_name).
+func (r *AgentRepository) List(ctx context.Context, statusFilter models.AgentStatus) ([]models.AgentCardData, error) {
+	var rows pgx.Rows
+	var err error
+
+	if statusFilter != "" {
+		rows, err = r.pool.Query(ctx, `
+			SELECT id, name, status, task, progress, session_key, channel, last_activity
+			FROM agents WHERE status = $1 ORDER BY name
+		`, string(statusFilter))
+	} else {
+		rows, err = r.pool.Query(ctx, `
+			SELECT id, name, status, task, progress, session_key, channel, last_activity
+			FROM agents ORDER BY name
+		`)
+	}
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+
+	return pgx.CollectRows(rows, func(row pgx.CollectableRow) (models.AgentCardData, error) {
+		var a models.AgentCardData
+		var task *string
+		var prog int
+		var lastActivity time.Time
+
+		if err := row.Scan(&a.ID, &a.DisplayName, &a.Status, &task, &prog,
+			&a.SessionKey, &a.Channel, &lastActivity); err != nil {
+			return a, err
+		}
+
+		a.CurrentTask = task
+		if prog > 0 || task != nil {
+			p := prog
+			a.TaskProgress = &p
+		}
+		a.LastActivity = lastActivity.UTC().Format(time.RFC3339)
+		a.Role = "agent"
+		return a, nil
+	})
+}
+
+// Update applies partial updates to an agent. Returns the updated agent.
+func (r *AgentRepository) Update(ctx context.Context, id string, req models.UpdateAgentRequest) (models.AgentCardData, error) {
+	// Build dynamic SET clause.
+	setClauses := []string{"last_activity = $2"}
+	args := []any{id, time.Now().UTC()}
+	argIdx := 3
+
+	if req.Status != nil {
+		setClauses = append(setClauses, fmt.Sprintf("status = $%d", argIdx))
+		args = append(args, string(*req.Status))
+		argIdx++
+	}
+	if req.CurrentTask != nil {
+		setClauses = append(setClauses, fmt.Sprintf("task = $%d", argIdx))
+		args = append(args, *req.CurrentTask)
+		argIdx++
+	}
+	if req.TaskProgress != nil {
+		setClauses = append(setClauses, fmt.Sprintf("progress = $%d", argIdx))
+		args = append(args, *req.TaskProgress)
+		argIdx++
+	}
+	if req.Channel != nil {
+		setClauses = append(setClauses, fmt.Sprintf("channel = $%d", argIdx))
+		args = append(args, *req.Channel)
+		argIdx++
+	}
+
+	// Build and execute
+	query := "UPDATE agents SET "
+	for i, clause := range setClauses {
+		if i > 0 {
+			query += ", "
+		}
+		query += clause
+	}
+	query += " WHERE id = $1"
+
+	ct, err := r.pool.Exec(ctx, query, args...)
+	if err != nil {
+		return models.AgentCardData{}, err
+	}
+	if ct.RowsAffected() == 0 {
+		return models.AgentCardData{}, fmt.Errorf("agent not found: %s", id)
+	}
+
+	return r.Get(ctx, id)
+}
+
+// Delete removes an agent. Returns nil even if the agent doesn't exist
+// (idempotent). Returns a wrapped error only on transport failures.
+func (r *AgentRepository) Delete(ctx context.Context, id string) error {
+	_, err := r.pool.Exec(ctx, `DELETE FROM agents WHERE id = $1`, id)
+	return err
+}
+
+// Count returns the total number of agents.
+func (r *AgentRepository) Count(ctx context.Context) (int, error) {
+	var n int
+	err := r.pool.QueryRow(ctx, `SELECT COUNT(*) FROM agents`).Scan(&n)
+	return n, err
+}
+
+// CountByStatus returns the number of agents with the given status.
+func (r *AgentRepository) CountByStatus(ctx context.Context, status models.AgentStatus) (int, error) {
+	var n int
+	err := r.pool.QueryRow(ctx, `SELECT COUNT(*) FROM agents WHERE status = $1`, string(status)).Scan(&n)
+	return n, err
+}