Triggers .github/workflows/whisper-server.yml to compile whisper.cpp's
server target on macOS arm64 / Linux x86_64 / Windows x86_64 and
upload archives to this tag's GitHub Release. SHA-256s emitted as
notice annotations to feed crates/sharing/whisper-manifest.json.

Bumped from v1.7.6 to v1.8.4 to pick up the i8mm/ggml fix that
makes macOS arm64 builds compile cleanly.