feat: Add liveness and readiness health check endpoints with database connectivity validation

- Add Ping method to PostgresProfileStore to check database connection status
- Add Ping method to ProfileRepository interface
- Add /api/v1/health/live endpoint for liveness checks (always returns alive if service is running)
- Add /api/v1/health/ready endpoint for readiness checks with database connectivity validation
- Add readinessHandler that returns SERVICE_UNAVAILABLE status when database ping fails

apps/carrier-connector/internal/repository/postgres.go

@@ -144,6 +144,15 @@ func (s *PostgresProfileStore) Close() error {
 	return sqlDB.Close()
 }
 
+// Ping checks if the database connection is alive.
+func (s *PostgresProfileStore) Ping() error {
+	sqlDB, err := s.db.DB()
+	if err != nil {
+		return err
+	}
+	return sqlDB.Ping()
+}
+
 // toRow maps domain -> row. Passthrough of CreatedAt/UpdatedAt lets GORM hooks
 // populate them on first save.
 func toRow(p *Profile) *profileRow {

apps/carrier-connector/internal/repository/profile.go

@@ -1,9 +1,9 @@
 package repository
 
 import (
-"context"
-"errors"
-"time"
+	"context"
+	"errors"
+	"time"
 )
 
 // ErrNotFound is returned when a profile lookup misses.
@@ -39,4 +39,5 @@ type ProfileRepository interface {
 	List(ctx context.Context, f ListFilter) ([]*Profile, int, error)
 	UpdateState(ctx context.Context, iccid, state string) (*Profile, error)
 	Delete(ctx context.Context, iccid string) error
+	Ping() error
 }

apps/carrier-connector/routes.go

@@ -15,6 +15,8 @@ import (
 func setupRoutes(router *gin.Engine, client *es2.ES2Client, repo repository.ProfileRepository) {
 	api := router.Group("/api/v1")
 	api.GET("/health", healthHandler)
+	api.GET("/health/ready", readinessHandler(repo))
+	api.GET("/health/live", livenessHandler)
 
 	esim := api.Group("/esim")
 	{
@@ -39,3 +41,38 @@ func healthHandler(c *gin.Context) {
 		"timestamp": time.Now().UTC(),
 	})
 }
+
+// livenessHandler returns a simple liveness check (always healthy if service is running).
+func livenessHandler(c *gin.Context) {
+	c.JSON(http.StatusOK, gin.H{
+		"status":    "alive",
+		"service":   "carrier-connector",
+		"timestamp": time.Now().UTC(),
+	})
+}
+
+// readinessHandler checks if the service is ready to accept requests (database connectivity).
+func readinessHandler(repo repository.ProfileRepository) gin.HandlerFunc {
+	return func(c *gin.Context) {
+		// Check database connectivity
+		if err := repo.Ping(); err != nil {
+			c.JSON(http.StatusServiceUnavailable, gin.H{
+				"status":    "not ready",
+				"service":   "carrier-connector",
+				"timestamp": time.Now().UTC(),
+				"error":     "database connection failed",
+				"details":   err.Error(),
+			})
+			return
+		}
+
+		c.JSON(http.StatusOK, gin.H{
+			"status":    "ready",
+			"service":   "carrier-connector",
+			"timestamp": time.Now().UTC(),
+			"checks": gin.H{
+				"database": "ok",
+			},
+		})
+	}
+}