Delegate TCL folding to server, fix bugs, and enhance stability

- Move TCL folding range computation from client to language server, avoiding duplicate regions.
- Serialize language server restarts to prevent multiple server instances running concurrently.
- Pin server-side Python dependencies to specific minor versions for improved stability and predictability.
- Make debug server connection non-fatal, allowing the language server to start even if the debugger isn't attached.
- Optimize semantic token generation by caching Tclint plugin commands.

package.json

@@ -134,10 +134,5 @@
     "esbuild": "^0.25.6",
     "prettier": "^3.4.2",
     "typescript": "^5.7.2"
-  },
-  "__metadata": {
-    "installedTimestamp": 1776513675781,
-    "targetPlatform": "undefined",
-    "size": 3267242
   }
 }