Maintainer review changes on the Edge TTS PR:
- edge-tts was added as a HARD base requirement, but the /api/tts handler is
designed optional (ImportError returns 503). Moved it out of requirements.txt
with an OPTIONAL comment + install hint; updated the 503 message from the
nonexistent 'see docs' to the actual install command. Keeps minimal base deps.
- PR shipped NO tests for a new auth+rate-limited+allowlisted network endpoint.
Added tests/test_issue2931_edge_tts_endpoint.py covering method (405), missing
text (400), over-length (400), voice allowlist (400), per-client rate limit
(429) — all in-process, no real synthesis/network.
