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

esbuild.js

@@ -1,19 +1,21 @@
 const esbuild = require("esbuild")
+const path = require("path")
 
 const production = process.argv.includes("--production")
 const watch = process.argv.includes("--watch")
 
 async function main() {
     const ctx = await esbuild.context({
+        absWorkingDir: __dirname,
         entryPoints: ["client/src/extension.ts"],
         bundle: true,
         format: "cjs",
         minify: production,
         sourcemap: !production,
-        sourcesContent: false,
+        sourcesContent: !production,
         platform: "node",
         // outdir: "out",
-        outfile: "./dist/extension.js",
+        outfile: path.join(__dirname, "dist", "extension.js"),
         external: ["vscode"],
         logLevel: "silent",
         plugins: [