feat: standalone web app mode without VS Code

[ronilaukkarinen]

Summary

Adds a standalone Node.js server that serves the Pixel Agents webview as a regular web app, removing the VS Code dependency entirely. The server auto-discovers all active Claude Code sessions across ~/.claude/projects/.

Related issues: #46, #120, #8

• Add standalone/ directory with HTTP + WebSocket server
• vscodeApi.ts auto-detects environment: VS Code postMessage or WebSocket
• Hide "+ Agent" button in standalone mode (no terminal spawning)
• Proper message ordering (assets -> agents -> layout) for correct character spawning

Usage

npm run build
cd standalone && npm install && node build.js
node dist/server.js    # http://localhost:3100

Test plan

• Run npm run build from repo root, then build and start standalone server
• Verify all active Claude Code sessions appear as animated characters
• Verify tool activity (typing, reading) animates correctly in real time
• Verify VS Code extension still works normally (no regression from vscodeApi.ts change)
• Verify "+ Agent" button is hidden in standalone mode

[florintimbuc]

Thanks for the PR @ronilaukkarinen! This is really close to the architectural direction we've been working toward. We've already extracted some shared modules (shared/assets/) to prepare the codebase for exactly this, a standalone core that multiple platforms (VS Code, Cursor, Electron, web) can build on.

I'll be posting an architectural proposal for the community soon that covers the shared module layer and multi-platform strategy. Your standalone server approach aligns well with it, so I'd love to sync up on a few things before we merge, mainly around importing from the shared modules instead of duplicating the asset loading and transcript parsing code.

Stay tuned for the proposal, and thanks again for pushing this forward! :)

[ronilaukkarinen]

Yeah, I just wanted to test this quickly, and since I'm more of a CLI person, I didn't have another option. I figured I might as well send a PR. Just a note, some AI was used to draft this, but you don't necessarily have to use it.