Rename server whisper to server asr with deprecation alias

[basnijholt]

Summary

agent-cli server whisper now serves multiple ASR backends (faster-whisper, MLX, transformers, NeMo/Parakeet), so the command name is increasingly misleading.

Proposal

Introduce agent-cli server asr as the canonical command and keep agent-cli server whisper as a temporary backward-compatible alias.

Suggested migration plan

1. Add server asr command entrypoint (same behavior/options as current server whisper).
2. Keep server whisper as alias for at least one release cycle.
3. Show a deprecation warning when server whisper is used.
4. Update docs/examples/help text to prefer server asr.
5. Update daemon/service docs naming where appropriate.
6. Remove alias in a later major/minor release (announce in release notes).

Why staged migration

A hard rename would be breaking and high-churn:

• many references in docs/tests/CLI examples
• daemon/service naming currently uses whisper

A staged approach gives users time to migrate safely.

Acceptance criteria

• agent-cli server asr is fully functional and documented.
• agent-cli server whisper works as alias with clear deprecation notice.
• Tests cover both command paths during migration window.