Remove duplicate Say To Me ID control

[JLarky]

Summary

• Remove the React/T3-owned Say To Me ID copy control from VoiceNotesBanner.
• Keep the generic <say-to-me-widget> as the sole owner of ID and Park controls.
• Add a focused assertion for exactly one widget element and no duplicate React ID control.

Dependency

Companion T3 change for Say To Me #619. This PR depends on STM pingdotgg#619 being merged and deployed so the generic widget owns the ID and Park controls. It targets main directly and is not stacked on another feature branch.

Validation

• Focused web tests: passed — 3 files, 29 tests (VoiceNotesBanner.test.tsx, SayToMeWidgetHost.test.tsx, widget.test.ts).
• Web typecheck: passed — vp run typecheck from apps/web.
• Formatting: passed — vp fmt --check on both changed files.
• Lint: passed — targeted vp lint on both changed files; one existing prefer-add-event-listener warning remains in VoiceNotesBanner.tsx:573.
• Isolated integration: blocked before authentication by the host runtime: the T3 server cannot load node-pty for linux-arm64 (pty.node missing), so no pairing URL was available. The web process itself served HTTP 200 on http://localhost:5733/.