EZC: Release workflow for dual binary distribution

[SchoolyB]

Ship both ez and ezc in releases

Currently releases only ship the Go `ez` binary. v3.0 needs to ship `ezc` alongside it with the runtime files.

Checklist

• Build `ezc` binary for Linux (amd64, arm64) and macOS (amd64, arm64)
• Bundle runtime files (`ez_runtime.c/h`, `ez_std.c/h`, etc.) with release
• Update `make install` to install both tools
• Update release workflow to produce both binaries
• Determine packaging: single archive with both, or separate downloads?