fix: add prompts/templates to backup + STDIO attach for docker-image servers

Two bugs fixed:

1. Backup completeness: JSON backup API now includes prompts and
   templates. Previously these were silently dropped during
   backup/restore, causing data loss on migration.

2. STDIO proxy for docker-image servers: servers with dockerImage
   but no packageName/command (like docmost) now use k8s Attach
   to connect to the container's PID 1 stdin/stdout instead of
   exec. This fixes "has no packageName or command" errors.

Changes:
- backup-service.ts: add BackupPrompt/BackupTemplate types, export them
- restore-service.ts: restore prompts (with project FK) and templates
- mcp-proxy-service.ts: sendViaPersistentAttach for docker-image STDIO
- orchestrator.ts: add attachInteractive to McpOrchestrator interface
- kubernetes-orchestrator.ts: implement attachInteractive via k8s Attach
- k8s-client-official.ts: expose Attach client

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

templates/gitea.yaml

@@ -0,0 +1,22 @@
+name: gitea
+version: "1.0.0"
+description: Gitea MCP server for repositories, issues, PRs, and code management
+dockerImage: "docker.gitea.com/gitea-mcp-server:latest"
+transport: STDIO
+repositoryUrl: https://gitea.com/gitea/gitea-mcp
+command:
+  - /app/gitea-mcp
+  - -t
+  - stdio
+# Health check disabled: STDIO health probe requires packageName (npm-based servers).
+# This server uses a custom dockerImage. Probe support for dockerImage STDIO servers is TODO.
+env:
+  - name: GITEA_HOST
+    description: Gitea instance URL (e.g. https://gitea.example.com)
+    required: true
+  - name: GITEA_ACCESS_TOKEN
+    description: Gitea personal access token
+    required: true
+  - name: GITEA_INSECURE
+    description: Allow self-signed certificates (true/false, default false)
+    required: false