Refresh ChatGPT voice DOM selectors

[qqrm]

Summary

• Update ChatGPT composer and dictation selectors for the current ProseMirror-based frontend.
• Reuse the current composer helpers across Ctrl+Enter, timestamps, preserve-on-send, DOM trimming, and wide chat relevance.
• Add tests for the current composer, dictation controls, sidebar Chats heading, and conversation-turn sections.

Validation

• npm run verify:ci - passed

Notes

• Validated against B:/_dl/cbe-chatgpt-frontend-bundle-2026-06-23-01-17-07.json.
• The supplied bundle did not include open delete/archive menus, delete confirmation modal, or temporary chat toggle state, so those interactive states remain covered by existing fallbacks rather than new DOM evidence.