Feature/vscode extension

[KillerQueen-Z]

• Add a VS Code sidebar extension (vscode-extension/) that provides the full RunCode agent experience
  inside VS Code — chat panel, tool execution, model switching, and all slash commands

  • Implement real-time balance tracking in the webview: balance updates synchronously on each usage
    event using local cost estimation (same approach as the Ink terminal UI), with RPC sync on turn
    completion
  • Add headless session API (src/api/vscode-session.ts) that decouples the agent loop from terminal
    I/O, enabling any host (VS Code, future web UI, etc.) to drive sessions via getUserInput + onEvent
  • Enhance /model command to render a full numbered model list via StreamEvent (previously only worked
    via console.error in TTY), allowing VS Code and other non-terminal hosts to display the picker
  • Add StreamStatusUpdate event type so model changes propagate to persistent UI elements without
    stderr
  • Two-tone banner rendering (gold "Run" + cyan "Code") in webview, matching CLI chalk output
  • Update README with VS Code extension install instructions and architecture diagram
  • Add dist/, .vscode/, vscode-extension/out/, *.vsix to .gitignore

  Test plan

  • npm run build in root — compiles cleanly
  • npm run compile in vscode-extension/ — compiles cleanly
  • F5 launch Extension Development Host — RunCode panel appears in sidebar
  • Send a message — agent responds, model and balance update in status strip
  • Balance decreases after each API call (no page reload needed)
  • /model displays numbered list in chat log
  • /model 3 or /model sonnet switches model, status strip updates
  • Stop button / Esc cancels in-flight requests
  • CLI runcode still works as before — no regressions

[1bcMax]

Thanks for the PR — good feature choices. /history, /delete, and the numbered model picker are all real user pain points. The headless session API is the right abstraction for multi-host support.

A few things before I can review further:

1. Remove dist/ from the PR. Compiled output shouldn't be committed — it'll be generated by CI. Please also remove vscode-extension/package-lock.json and vscode-extension/out/ if present.

2. Split extension.ts (782 lines) into smaller modules. Suggestion: webview-provider.ts, session-manager.ts, and ui-renderer.ts. One file doing webview setup + session management + HTML rendering + balance tracking is too much to review or maintain.

3. Version bump should be a separate commit (2.5.28 → 2.5.29), not mixed into the feature.

4. Can you explain the design decision behind the headless session API (vscode-session.ts) — why decouple via getUserInput + onEvent callbacks rather than importing the agent loop directly? Want to make sure we're aligned on the architecture before this ships.

Looking forward to the updated PR.