Log MCP protocol messages in the inspector console

[abewheel]

Summary

• Adds colored console logs for all MCP App protocol messages in the inspector, covering both directions (host → app and app → host)
• Logs incoming app requests via a window message listener that filters out sunpeak-internal traffic
• Logs outgoing host notifications (setHostContext, sendToolInput, sendToolResult, etc.) and response acks for all bridge handlers
• Fixes a bug where early returns in openLink URL validation skipped the consistent return path

Test plan

• pnpm --filter sunpeak typecheck passes
• pnpm --filter sunpeak lint passes
• pnpm --filter sunpeak test -- --run passes (233 tests)
• Run sunpeak dev on a sample app and verify colored [MCP ↑] / [MCP ↓] logs appear in browser console
• Verify no sunpeak-internal messages (fence, injectState, sandbox-proxy-ready) appear in the logs