feat(debug): enable Python debug workflow and debug server integration

Adds an end-to-end Python debug workflow for the extension.
Includes a new prepare-debug.ps1 script and a VS Code task.
Extends the Python server and extension to coordinate a debug session and safe startup.

- Add prepare-debug.ps1 and a VS Code task to build the debug bundle
- Enable Python debug wiring in the server and tests
- Ensure a single stable Python debug session during startup

client/package-lock.json

@@ -14,6 +14,7 @@
         "vscode-languageclient": "^9.0.1"
       },
       "devDependencies": {
+        "@types/fs-extra": "^11.0.4",
         "@types/node": "^22.10.5",
         "@types/vscode": "^1.96.0"
       },
@@ -21,6 +22,27 @@
         "vscode": "^1.96.0"
       }
     },
+    "node_modules/@types/fs-extra": {
+      "version": "11.0.4",
+      "resolved": "https://registry.npmjs.org/@types/fs-extra/-/fs-extra-11.0.4.tgz",
+      "integrity": "sha512-yTbItCNreRooED33qjunPthRcSjERP1r4MqCZc7wv0u2sUkzTFp45tgUfS5+r7FrZPdmCCNflLhVSP/o+SemsQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@types/jsonfile": "*",
+        "@types/node": "*"
+      }
+    },
+    "node_modules/@types/jsonfile": {
+      "version": "6.1.4",
+      "resolved": "https://registry.npmjs.org/@types/jsonfile/-/jsonfile-6.1.4.tgz",
+      "integrity": "sha512-D5qGUYwjvnNNextdU59/+fI+spnwtTFmyQP0h+PfIOSkNfpU6AOICUOkm4i0OnSk+NyjdPJrxCDro0sJsWlRpQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@types/node": "*"
+      }
+    },
     "node_modules/@types/node": {
       "version": "22.10.5",
       "resolved": "https://registry.npmjs.org/@types/node/-/node-22.10.5.tgz",