release-auto: cargo-zigbuild fails on musl targets — `Syntax error: ")" unexpected` at line 10

[zackees]

Symptom

The auto-release workflow run 26701593735 (and its rerun) both fail on the two *-unknown-linux-musl matrix entries with:

```
/home/runner/work/_temp/setup-soldr-soldr/bin/cargo-zigbuild-0.22.3/cargo-zigbuild: 10: Syntax error: ")" unexpected
```

Both aarch64-unknown-linux-musl and x86_64-unknown-linux-musl fail at the soldr cargo zigbuild --release --target ... step (template_native_build.yml:101).

Impact

Build failures cascade — `Build PyPI wheels`, `Publish GitHub release`, and `Publish PyPI` are all SKIPPED. fbuild 2.2.12 is tagged on main (commit 09c1262) but is NOT on PyPI. This blocks FastLED/FastLED#2631 and FastLED/FastLED#2633 ingestion.

Diagnosis pointers

• The cargo-zigbuild binary at /home/runner/work/_temp/setup-soldr-soldr/bin/cargo-zigbuild-0.22.3/cargo-zigbuild is being shell-interpreted (line-10 syntax error on )), which suggests the file is either truncated, a non-script ELF/wrapper being misread, or a script with a malformed shebang. The cached path lives under setup-soldr's bin cache, so this may be a soldr cache-population regression rather than an upstream cargo-zigbuild bug.
• 2.2.11 (released 2026-05-30 23:10) used the same cargo-zigbuild==0.22.3 (PyPI latest, released 2026-04-26) successfully — so it's not the cargo-zigbuild version itself.
• Reproducible: failed on initial run AND after gh run rerun --failed.

Workarounds considered

1. Pin cargo-zigbuild to an older PyPI version — not the issue (0.22.3 also worked for 2.2.11).
2. Strip musl matrix entries from release-auto.yml — works around but loses the wheels.
3. Re-pin/refresh the soldr bin cache for cargo-zigbuild-0.22.3 — most likely correct fix.

Reproduce

```
gh run rerun 26701593735 --repo FastLED/fbuild --failed
```

Blocking

FastLED-side ingestion PR for #325/#327 alias fixes is on hold until 2.2.12 publishes.