fix(asr): resolve native models from the shared catalog

[Alphaxiaoteng]

Summary

• resolve desktop-native GGML filenames from the shared ASR model catalog
• preserve the existing small and medium filename fallbacks for compatible local caches
• add executable coverage for every supported tier and unknown model IDs

Problem

The shared catalog already downloads a GGML companion for Whisper Large v3 Turbo, but the desktop worker maintained a separate model map that did not include its model ID. As a result, a complete Large v3 Turbo download could not be selected by the native worker and the app fell back to the browser ONNX path.

This is related to #120 and specifically addresses the Large v3 Turbo desktop-native routing gap. It does not claim to fix the separate Medium ONNX load error or interrupted-download reset reported in that issue.

Verification

• regression A/B: the old four-entry mapping fails the new Large v3 Turbo assertion; the fix passes all five tiers plus the unknown-model boundary
• npm test
• npm run lint
• npm run build
• npm run verify:desktop-inference
• npm run verify:speech-providers
• npm run verify:agent-skill

No UI behavior changed, so no screenshot is applicable. Developed with Codex assistance and independently reviewed and tested.