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

.vscode/tasks.json

@@ -0,0 +1,26 @@
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "NX Post Support: Compile Debug",
+            "type": "process",
+            "command": "powershell.exe",
+            "args": [
+                "-NoLogo",
+                "-NoProfile",
+                "-ExecutionPolicy",
+                "Bypass",
+                "-Command",
+                "& { param([string]$WorkspaceRoot, [string]$DebugRoot); $scriptRoot = $WorkspaceRoot; if ($scriptRoot.StartsWith('\\\\?\\')) { $scriptRoot = $scriptRoot.Substring(4) }; & (Join-Path $scriptRoot '.vscode\\prepare-debug.ps1') -WorkspaceRoot $WorkspaceRoot -DebugRoot $DebugRoot; exit $LASTEXITCODE }",
+                "${workspaceFolder}",
+                "${env:TEMP}\\nx-post-support-vscode-debug"
+            ],
+            "problemMatcher": [],
+            "presentation": {
+                "reveal": "always",
+                "panel": "dedicated",
+                "clear": true
+            }
+        }
+    ]
+}