fix(ws): prevent host message self-delivery

[kermanx]

Summary

• exclude the embedded WebSocket host from its own broadcasts
• preserve guest-to-host broadcast and targeted delivery
• add routing regression coverage with terminal escape-sequence payloads

Root cause

Host Locally messages bypass the normal WebSocket sender exclusion. Terminal output broadcast by the host was therefore delivered back as terminal input and written into the PTY.

Verification

• pnpm test
• pnpm typecheck
• pnpm exec eslint src/sync/ws/server.ts src/sync/ws/server.test.ts package.json
• pnpm build

Closes #12