feat(db): implement PostgreSQL monitoring and maintenance features

Added PostgreSQL monitoring and maintenance capabilities to the API, including new endpoints for instance-level metrics, maintenance operations, and job scheduling. Updated the HTTP API to support PostgreSQL monitoring routes and integrated a background scheduler for metrics collection. Enhanced the CLI with database commands for maintenance tasks. Updated documentation to reflect these changes.

internal/httpapi/server.go

@@ -10,6 +10,7 @@ import (
 	"strings"
 
 	"evobgp/internal/jobs"
+	"evobgp/internal/pgmonitor"
 	"evobgp/internal/store"
 
 	"github.com/jackc/pgx/v5/pgxpool"
@@ -19,6 +20,7 @@ import (
 type Server struct {
 	store       store.Backend
 	pgPool      *pgxpool.Pool
+	pgMonitor   *pgmonitor.Service
 	jobs        *jobs.Registry
 	bundlePriv  ed25519.PrivateKey
 	keyResolver *apiKeyResolver
@@ -63,9 +65,14 @@ func New(opts Options) (*Server, error) {
 	if err != nil {
 		return nil, err
 	}
+	var pgMon *pgmonitor.Service
+	if pool != nil {
+		pgMon = pgmonitor.NewService(pool)
+	}
 	s := &Server{
 		store:       backend,
 		pgPool:      pool,
+		pgMonitor:   pgMon,
 		jobs:        reg,
 		bundlePriv:  priv,
 		keyResolver: resolver,
@@ -89,3 +96,10 @@ func (s *Server) Store() store.Backend { return s.store }
 
 // Jobs exposes the in-process async job registry (for scheduler / evobgp-all).
 func (s *Server) Jobs() *jobs.Registry { return s.jobs }
+
+// StartBackground starts PostgreSQL monitoring scheduler until ctx is cancelled.
+func (s *Server) StartBackground(ctx context.Context) {
+	if s != nil && s.pgPool != nil {
+		pgmonitor.StartScheduler(ctx, s.pgPool)
+	}
+}