fix: update whisper-rs to 0.15.1 for macOS ARM support

[wilcorrea]

🐛 Problem

The v0.4.0 release build failed for macOS ARM due to a compilation error in whisper-rs-sys v0.13.1:

error: always_inline function 'vmmlaq_s32' requires target feature 'i8mm'

The GitHub Actions macOS ARM runner doesn't support the required CPU instructions when compiling whisper.cpp with the 0.14 version.

✅ Solution

Update to whisper-rs 0.15.1, which includes:

• Better ARM64 support and compilation fixes
• Updated whisper.cpp bindings
• Simplified API (breaking changes handled)

📝 Changes

Dependencies

• whisper-rs: 0.14.4 → 0.15.1
• whisper-rs-sys: 0.13.1 → 0.14.1

API Adaptations

• full_n_segments() now returns i32 directly (no Result)
• full_get_segment_text() replaced with get_segment()
• Use Display trait implementation for text extraction: format!("{}", segment)

🧪 Test Plan

• cargo check passes locally
• Build succeeds on macOS ARM (GitHub Actions)
• Build succeeds on macOS Intel
• Build succeeds on Linux
• Build succeeds on Windows
• Voice-to-text transcription still works correctly
• No regressions in transcription quality

📎 References

• Closes chore: update voice-to-text dependencies to latest versions #3
• Blocks v0.4.0 release (fixes ARM build failure)
• CodeRabbit review comment: feat: add offline voice-to-text with Whisper and UI improvements #2 (comment)

Summary by CodeRabbit

• Dependencies

  • Updated transcription library to the latest version for improved compatibility.

• Bug Fixes

  • Improved transcription reliability by refining error handling to better manage edge cases during text extraction.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

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📝 Walkthrough

Walkthrough

Updated whisper-rs dependency from 0.14 to 0.15 and refactored transcriber error handling to use direct segment counting and fallback-based retrieval instead of Result-based error mapping.

Changes

Cohort / File(s)	Summary
Dependency Update apps/tauri/src-tauri/Cargo.toml	Bumped whisper-rs from 0.14 to 0.15.
Error Handling Refactor apps/tauri/src-tauri/src/whisper/transcriber.rs	Replaced per-segment error-prone retrieval with direct numeric segment count via state.full_n_segments() and changed text extraction to use fallback iteration with get_segment(i), silencing segment retrieval errors while propagating transcription errors.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 A whisper update floats through the air,
Segments counted with simpler care,
Errors hushed in the retrieval flow,
Cleaner transcription steals the show! ✨

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title references updating whisper-rs to 0.15.1 for macOS ARM support, which aligns with the main changes in the PR (dependency update and API adaptations).
Linked Issues check	✅ Passed	The PR partially addresses issue #3 by updating whisper-rs (0.14 to 0.15.1) and adapting the transcription API, but does not address cpal, rubato, or reqwest updates listed in the medium/low priority objectives.
Out of Scope Changes check	✅ Passed	All changes are directly related to the whisper-rs dependency update and necessary API adaptations in transcriber.rs; no unrelated modifications are present.

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✨ Finishing Touches

• 📝 Generate docstrings (stacked PR)
• 📝 Generate docstrings (commit on current branch)

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch chore/update-whisper-deps

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