fix(database): auto-generate missing CA cert on SSL regeneration

Prevent null CA certificate access during database SSL certificate regeneration
across KeyDB, MariaDB, MongoDB, MySQL, PostgreSQL, and Redis components.

If no CA certificate exists, attempt to generate one and re-query; if still
missing, dispatch a clear error and stop regeneration gracefully.

Add `SslCertificateRegenerationTest` coverage for missing-CA and CA-query
scenarios to prevent regressions.

openapi.json

@@ -2722,8 +2722,7 @@
                                     },
                                     "is_preserve_repository_enabled": {
                                         "type": "boolean",
-                                        "default": false,
-                                        "description": "Preserve repository during deployment."
+                                        "description": "Preserve git repository during application update. If false, the existing repository will be removed and replaced with the new one. If true, the existing repository will be kept and the new one will be ignored. Default is false."
                                     }
                                 },
                                 "type": "object"
@@ -7275,6 +7274,22 @@
                         "schema": {
                             "type": "integer"
                         }
+                    },
+                    {
+                        "name": "pull_request_id",
+                        "in": "query",
+                        "description": "Preview deployment identifier. Alias of pr.",
+                        "schema": {
+                            "type": "integer"
+                        }
+                    },
+                    {
+                        "name": "docker_tag",
+                        "in": "query",
+                        "description": "Docker image tag for Docker Image preview deployments. Requires pull_request_id.",
+                        "schema": {
+                            "type": "string"
+                        }
                     }
                 ],
                 "responses": {
@@ -12735,6 +12750,10 @@
                     "pull_request_id": {
                         "type": "integer"
                     },
+                    "docker_registry_image_tag": {
+                        "type": "string",
+                        "nullable": true
+                    },
                     "force_rebuild": {
                         "type": "boolean"
                     },