v0.3.28

v0.3.28 — 8 GitHub issue fixes

- #416: ResourceQuota default max_cost=0.0 (unlimited, stops blocking fresh agents)
- #411: Session reset clears scheduler usage tracking
- #414: Web search returns errors not fake success
- #399: MCP stdio Content-Length framing + correct version
- #400: Non-TTY init auto-falls back to quick mode
- #405: python3→python fallback for Windows Browser Hand
- #395: Embedding driver passes custom base URL from provider_urls
- #404: Bluesky seenAt parameter URL-encoded