feat: add VS Code configuration for debugging bun

- Add .vscode/extensions.json recommending oven.bun-vscode.
- Add .vscode/launch.json with Bun debug configurations for various scripts.
- Add .vscode/settings.json for TypeScript SDK, debug options, and file exclusions.
- Remove .vscode/ entry from .gitignore.
- Refactor ingest.ts: increase chunk size to 8192 and overlap to 200, raise large document threshold, remove <h1>/<h2> separators, skip sections containing only headings or minimal content, and add warnings for very small chunks.

.vscode/extensions.json

@@ -0,0 +1,3 @@
+{
+  "recommendations": ["oven.bun-vscode"]
+}