#5 feat: adopt typed yt-dlp broker and reproducible CI

Summary

• migrate host-managed downloads to the typed yt-dlp contract
• add complete WASM ABI smoke coverage and pinned reproducible CI
• use upstream Extism 1.30.0

Validation

• 79 unit tests and the WASM smoke pass
• native and WASM Clippy pass with warnings denied
• release WASM build and cargo audit pass

Linear: MAT-129, MAT-131

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Summary by cubic

Switch downloads to the typed run_ytdlp broker and harden reproducible CI with split verify/release workflows repinned to canonical upstream SHAs, gated by tags, and restricted to the repository owner. Bumps the plugin to 1.3.0, requires Vortex host 0.2.0, and adds a release WASM ABI smoke test (addresses Linear MAT-129, MAT-131).

• New Features

  • Adopt typed run_ytdlp broker: replace run_subprocess, send only url/format/output_dir/audio_only, and parse the typed response.
  • Add tests/wasm_smoke.rs to validate exports and the broker contract end-to-end.
  • CI: split verification and release via reusable configs, repin workflows by commit to canonical upstream, pin Rust toolchain (1.95.0), and restrict release to owner tag builds.
  • Bump extism to =1.30.0.

• Migration

  • Host must expose the typed run_ytdlp function (Vortex ≥ 0.2.0) and subprocess: ["yt-dlp"] capability.
  • No user-facing changes; the plugin cannot set binaries, args, timeouts, env, or cwd.

Summary by CodeRabbit

• New Features
  • Adaptive media downloads now use the host’s typed download service.
  • Download requests provide structured media details, including format, audio-only mode, and output location.
• Improvements
  • Updated compatibility requirements to Vortex 0.2.0 or later.
  • Strengthened host-controlled network access and download execution safeguards.
• Documentation
  • Clarified supported host capabilities and adaptive stream download behavior.
• Release
  • Updated the plugin version to 1.3.0.