[cardin]

feat(release): add a static x86_64 Linux musl binary

Fixes #102

Summary

• Add x86_64-unknown-linux-musl to the release build matrix without replacing GNU/Linux assets.
• Install the musl linker for that target and let the existing artifact/checksum/publish steps include the additional binary.
• Before publishing, smoke-test the musl binary in Debian Bullseye (glibc 2.31) and Alpine containers without installing a compiler or compatibility libraries.
• Document when to choose the static binary and how to verify its checksum.

Motivation

The v0.9.4 x86_64 GNU release binary requires GLIBC_2.32, GLIBC_2.33, and GLIBC_2.34, so it fails to start on a host running glibc 2.31. A locally built musl binary works on the affected machine, including interactive annotation through the unofficial OpenCode adapter.

An additional musl asset provides a download-only workaround without requiring a system glibc upgrade or a Rust/C build environment on users' machines.

Tests

scripts/smoke-musl.sh accepts a binary path and verifies:

• The executable reports the workspace version.
• A fresh document has no annotations.
• Creating and exporting an annotation preserves the selected quote and feedback.
• A document snapshot renders the expected heading.

The release workflow runs this script inside both minimal Linux environments.

Local validation completed against upstream commit f35f70ebd392198f0ab0299ecbdc9c834184c899:

• Built the checked-out source with Rust 1.96 in Alpine using cargo build --release --locked -p plannotator-tui --target x86_64-unknown-linux-musl --jobs 2.
• Ran the smoke script against that binary in both debian:bullseye-slim and alpine:3.24; both passed.
• Validated shell syntax, parsed the release YAML, checked the matrix and build-step shell syntax, and ran git diff --check.
• cargo fmt --all --check passed in Docker.
• cargo clippy --workspace --all-targets --locked --jobs 2 -- -D warnings passed in Docker with the musl target.

The GitHub-hosted Ubuntu/musl-tools build path and the release publishing workflow have not been executed locally. Full workspace tests were not run locally for this release-configuration/docs-only patch; normal upstream CI still needs to pass.

Scope

• x86_64 only: this is the architecture of the confirmed reproduction and tested workaround.
• No application-code, dependency, Homebrew tap, or existing asset-name changes.
• ARM64 musl support can follow separately with native validation.