feat: add unbrowse-web-api skill — reverse-engineer website APIs without a browser

[tonyagents]

Skill: unbrowse-web-api

Adds a skill for Unbrowse — an open-source tool that reverse-engineers a website's hidden APIs from browser traffic and calls them directly.

Why it matters:

• ~100x faster than headless browser (50–200ms vs 5–30s per action)
• ~80% cheaper — no Playwright/Puppeteer overhead
• ~40x fewer tokens (~200 vs ~8,000 per action)
• 100% local, free, open source (AGPL-3.0)
• Shared skill marketplace: capture once, reuse everywhere

What's included

• skills/unbrowse-web-api/SKILL.md — full instructional guide
• marketplace.json — added unbrowse-skills plugin block

Skill covers

• Installing Bun + running the local server
• Single-call intent resolution (/v1/intent/resolve)
• Marketplace search and skill reuse
• Dry-run / confirm_unsafe pattern for mutations
• Auth flow for gated sites (interactive + yolo mode)
• Feedback submission to improve marketplace reliability
• Debugging and skill verification
• Error handling table

Verification

All endpoints verified against the unbrowse-ai/unbrowse source:

• /v1/intent/resolve, /v1/search, /v1/search/domain — confirmed in router
• /v1/skills/:id/execute with dry_run and confirm_unsafe — confirmed in source
• /v1/auth/login with yolo mode — confirmed
• /v1/feedback, /v1/skills/:id/verify, /v1/stats/summary — all confirmed
• bun src/index.ts startup with UNBROWSE_TOS_ACCEPTED=1 — confirmed in README