feat: implement service-specific Modal API keys with auto processor pattern (#528)

* fix: refactor modal API key configuration for better separation of concerns

- Split generic MODAL_API_KEY into service-specific keys:
  - TRANSCRIPT_API_KEY for transcription service
  - DIARIZATION_API_KEY for diarization service
  - TRANSLATE_API_KEY for translation service
- Remove deprecated *_MODAL_API_KEY settings
- Add proper validation to ensure URLs are set when using modal processors
- Update README with new configuration format

BREAKING CHANGE: Configuration keys have changed. Update your .env file:
- TRANSCRIPT_MODAL_API_KEY → TRANSCRIPT_API_KEY
- LLM_MODAL_API_KEY → (removed, use TRANSCRIPT_API_KEY)
- Add DIARIZATION_API_KEY and TRANSLATE_API_KEY if using those services

* fix: update Modal backend configuration to use service-specific API keys

- Changed from generic MODAL_API_KEY to service-specific keys:
  - TRANSCRIPT_MODAL_API_KEY for transcription
  - DIARIZATION_MODAL_API_KEY for diarization
  - TRANSLATION_MODAL_API_KEY for translation
- Updated audio_transcript_modal.py and audio_diarization_modal.py to use modal_api_key parameter
- Updated documentation in README.md, CLAUDE.md, and env.example

* feat: implement auto/modal pattern for translation processor

- Created TranscriptTranslatorAutoProcessor following the same pattern as transcript/diarization
- Created TranscriptTranslatorModalProcessor with TRANSLATION_MODAL_API_KEY support
- Added TRANSLATION_BACKEND setting (defaults to "modal")
- Updated all imports to use TranscriptTranslatorAutoProcessor instead of TranscriptTranslatorProcessor
- Updated env.example with TRANSLATION_BACKEND and TRANSLATION_MODAL_API_KEY
- Updated test to expect TranscriptTranslatorModalProcessor name
- All tests passing

* refactor: simplify transcript_translator base class to match other processors

- Moved all implementation from base class to modal processor
- Base class now only defines abstract _translate method
- Follows the same minimal pattern as audio_diarization and audio_transcript base classes
- Updated test mock to use _translate instead of get_translation
- All tests passing

* chore: clean up settings and improve type annotations

- Remove deprecated generic API key variables from settings
- Add comments to group Modal-specific settings
- Improve type annotations for modal_api_key parameters

* fix: typing

* fix: passing key to openai

* test: fix rtc test failing due to change on transcript

It also correctly setup database from sqlite, in case our configuration
is setup to postgres.

* ci: deactivate translation backend by default

* test: fix modal->mock

* refactor: implementing igor review, mock to passthrough

server/pyproject.toml

@@ -40,6 +40,7 @@ dependencies = [
     "psycopg2-binary>=2.9.10",
     "llama-index>=0.12.52",
     "llama-index-llms-openai-like>=0.4.0",
+    "pytest-env>=1.1.5",
 ]
 
 [dependency-groups]
@@ -83,6 +84,10 @@ packages = ["reflector"]
 [tool.coverage.run]
 source = ["reflector"]
 
+[tool.pytest_env]
+ENVIRONMENT = "pytest"
+DATABASE_URL = "sqlite:///test.sqlite"
+
 [tool.pytest.ini_options]
 addopts = "-ra -q --disable-pytest-warnings --cov --cov-report html -v"
 testpaths = ["tests"]