HH-445: deploy production observability and runbooks (#96)

* HH-445: deploy production observability and runbooks

* fix(ops): share production database DSN

* fix(HH-445): enforce database TLS gate

* fix(HH-445): preserve production serve command

* fix(prod): require external database dependencies

* fix(prod): unify database host rejection gates

* test(prod): enforce exact database TLS runbook contract

---------

Co-authored-by: Rogee <rogee@ipao.vip>

backend/cmd/migrate/main.go

@@ -32,6 +32,12 @@ func main() {
 	}
 
 	dbURL := cfg.Database.MigrateDSN()
+	if cfg.Server.Mode == "release" {
+		if err := config.ValidateProductionDatabaseDSN(dbURL); err != nil {
+			fmt.Fprintf(os.Stderr, "Error validating database DSN: %v\n", err)
+			os.Exit(1)
+		}
+	}
 	migrationsPath := cfg.Database.GetMigrationsPath()
 
 	switch command {