Add DeepInfra transcription provider

[anamanlab]

Summary

• add a DeepInfra transcription provider using the OpenAI-compatible audio transcription endpoint
• wire --api deepinfra into the Sapat CLI
• support Sapat's existing --correct flow through DeepInfra's OpenAI-compatible chat endpoint
• document DeepInfra transcription and chat environment variables in the README
• add mocked unittest coverage for transcription payloads and corrected transcript chat calls

Validation

• PYTHONPATH=src py -3 -m unittest discover -s tests
• PYTHONPATH=src py -3 -m py_compile src/sapat/transcription/deepinfra.py src/sapat/script.py
• PYTHONPATH=src py -3 -m sapat.script --help
• git diff --check

[anamanlab]

Reviewer note: the visible red status contexts are external Continue AI statuses, not GitHub Actions jobs from this repository. gh pr checks --required reports no required checks on this branch, and the GitHub check-runs API returns no check runs for the commit. The local validation I ran is listed in the PR body:

• PYTHONPATH=src py -3 -m unittest discover -s tests
• PYTHONPATH=src py -3 -m py_compile src/sapat/transcription/deepinfra.py src/sapat/script.py
• PYTHONPATH=src py -3 -m sapat.script --help
• git diff --check

[anamanlab]

Follow-up hardening commit pushed: DeepInfra now also supports Sapat's existing --correct path via DeepInfra's OpenAI-compatible chat endpoint.

Re-ran local validation after the commit:

• PYTHONPATH=src py -3 -m unittest discover -s tests (2 tests)
• PYTHONPATH=src py -3 -m py_compile src/sapat/transcription/deepinfra.py src/sapat/script.py
• PYTHONPATH=src py -3 -m sapat.script --help
• git diff --check

All pass locally. The visible Continue statuses still report agent execution errors rather than repository test failures.

[nibzard]

Thanks for the contribution, but after reviewing all incoming PRs we've decided not to merge this one.

Reason: This is a duplicate of PR #49 which has a stronger implementation. Neither will be merged individually — we're incorporating DeepInfra support in our architecture refactor instead.

We've refactored the codebase into a provider plugin architecture (see PR coming soon on feat/provider-plugin-architecture) and are incorporating provider support differently. Closing this PR.