fix(stt): map cloud-only model names to valid local size for faster-whisper (#2544)

Cherry-picked from PR #2545 by @Mibayy.

The setup wizard could leave stt.model: "whisper-1" in config.yaml.
When using the local faster-whisper provider, this crashed with
"Invalid model size 'whisper-1'". Voice messages were silently ignored.

_normalize_local_model() now detects cloud-only names (whisper-1,
gpt-4o-transcribe, etc.) and maps them to the default local model
with a warning. Valid local sizes (tiny, base, small, medium, large-v3)
pass through unchanged.

- Renamed _normalize_local_command_model -> _normalize_local_model
  (backward-compat wrapper preserved)
- 6 new tests including integration test
- Added lowercase AUTHOR_MAP alias for @Mibayy

Closes #2544

scripts/release.py

@@ -82,6 +82,7 @@ AUTHOR_MAP = {
     "462836+jplew@users.noreply.github.com": "jplew",
     "nish3451@users.noreply.github.com": "nish3451",
     "Mibayy@users.noreply.github.com": "Mibayy",
+    "mibayy@users.noreply.github.com": "Mibayy",
     "135070653+sgaofen@users.noreply.github.com": "sgaofen",
     "nocoo@users.noreply.github.com": "nocoo",
     "30841158+n-WN@users.noreply.github.com": "n-WN",