Etapa 2 PR3: VSCode extension for the DAP debugger

[jig]

Summary

Phase C of the Etapa 2 plan: a VSCode extension at tools/vscode-lisp/
that consumes the DAP server shipped in PR2.

• Syntax highlighting for .lisp / .mal: a TextMate grammar
  covering comments, strings, numbers, keywords, special forms (def,
  defmacro, let, fn, if, do, try, catch, finally, throw, quote,
  quasiquote, unquote, splice-unquote, recur, macroexpand), constants
  (true/false/nil), quoted forms, and ordinary symbols.
• Language configuration: line comments, balanced brackets,
  auto-closing pairs.
• Debugger integration: registers type: "lisp" debug
  configurations and a DebugAdapterDescriptorFactory that spawns the
  lispdebug-build interpreter as the DAP server over stdio.
• DebugConfigurationProvider filling in defaults when the user
  runs F5 without a launch.json.
• Settings: lisp.debugAdapter.command (default lisp-debug) and
  lisp.debugAdapter.extraArgs.

Build & install (local)

# 1. Build the debug-build interpreter and put it on PATH
cd $REPO_ROOT
go build -tags lispdebug -o lisp-debug ./cmd/lisp
sudo install lisp-debug /usr/local/bin/

# 2. Build and install the extension
cd tools/vscode-lisp
npm install
npm run compile
npx @vscode/vsce package
code --install-extension vscode-lisp-*.vsix

Marketplace publishing is intentionally out of scope — .vsix only.

What's NOT in this PR

• LSP features (hover, completion, go-to-definition, diagnostics).
  Those land in PR4 (LSP backend) and PR5 (LSP client + docs).
• Conditional breakpoints, watch expressions, function breakpoints.
  Etapa 3 if ever.
• Editing/Format/Code-actions support.

Test plan

• npm install and npm run compile succeed (TypeScript clean).
• package.json validates (no schema errors).
• .gitignore excludes node_modules/, out/, *.vsix.
• Extension files are non-empty and well-formed (out/extension.js
  generated, extension.js.map produced).
• Go build/test suite still green (no Go changes in this PR).
• Manual test in VSCode: open a .lisp file, F5, set a breakpoint,
  step over/in/out, inspect call stack and locals. (Requires
  reviewer to install the .vsix and the lispdebug build of the
  interpreter.)

🤖 Generated with Claude Code