Complete the tlbx repository cutover

What's Changed

• Canonicalized release, source, security, documentation, and installer links on the renamed tlbx-ai/tlbx repository
• Moved new voice and transcription traffic to api.tlbx.ai while preserving midterm.tlbx.ai as a compatibility proxy for older clients
• Updated the visible command-line and GitHub artwork to the tlbx name without changing executable, service, certificate, settings, or session identities
• Kept the former MidTerm repository coordinate as an explicit updater fallback and the old GitHub Pages installer paths as durable compatibility shims
• Serialized the small in-process integration suite so Program environment setup cannot race its environment-contract test