docs(contributing): Add "Setting up a Debugger" section (#4421)

Co-authored-by: GitHub Action <action@github.com>

.vscode/launch.example.json

@@ -0,0 +1,11 @@
+{
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "type": "bun",
+      "request": "attach",
+      "name": "opencode (attach)",
+      "url": "ws://localhost:6499/"
+    }
+  ]
+}

.vscode/settings.example.json

@@ -0,0 +1,5 @@
+{
+  "recommendations": [
+    "oven.bun-vscode"
+  ]
+}