refactor: pivot from ssh proxy to distributed api model

- Delete SSHFileAdapter, IFileAdapter, LocalFileAdapter (SSH/SFTP stack)
- Remove ssh2, ssh2-sftp-client dependencies; add http-proxy-middleware, http-proxy
- NodeRegistry: remote nodes no longer use Dockerode TCP; new getProxyTarget() returns {apiUrl, apiToken}
- NodeRegistry.testConnection: remote nodes use HTTP GET /api/auth/check instead of docker.info()
- DatabaseService: Node interface swaps SSH/TLS fields for api_url + api_token; legacy columns preserved for DB compat
- FileSystemService: reverted to clean local-only fs.promises; adapter pattern fully removed
- ComposeService: executeRemote() and SSH log streaming deleted; local-only execution remains
- index.ts: add /api/auth/generate-node-token endpoint (long-lived JWT, scope:node_proxy)
- index.ts: authMiddleware now accepts Bearer token in addition to cookie (Sencho-to-Sencho auth)
- index.ts: remote HTTP proxy middleware intercepts all /api/ requests for remote nodes, strips x-node-id, injects Authorization header, proxies to api_url
- index.ts: WS upgrade handler proxies WebSocket connections for remote nodes via http-proxy wsProxyServer
- NodeManager.tsx: form reduced to Name, API URL, API Token; Generate Node Token button added inline
- NodeContext.tsx: Node interface updated to api_url/api_token

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.claude/settings.local.json

@@ -0,0 +1,21 @@
+{
+  "env": {
+    "includeCoAuthoredBy": "false"
+  },
+  "permissions": {
+    "allow": [
+      "Bash(xargs wc:*)",
+      "Bash(grep -c \"TODO\\\\|FIXME\" /c/Users/Boris/Documents/Projects/Sencho/backend/src/services/*.ts)",
+      "Bash(git checkout:*)",
+      "Bash(git pull:*)",
+      "Bash(git add:*)",
+      "Bash(git commit:*)",
+      "Bash(git push:*)",
+      "mcp__github__create_pull_request",
+      "Bash(gh auth:*)",
+      "Bash(npm uninstall:*)",
+      "Bash(npm install:*)",
+      "Bash(npx tsc:*)"
+    ]
+  }
+}