- Make TALOS_VERSION overridable (?=) and extract from git tag
- Workflow builds Pi5 then Pi4 (clean re-checkout for different kernel config)
- Separate installer images: <tag>-rpi5 and <tag>-rpi4
- Separate metal images: metal-arm64-rpi5.raw.zst and metal-arm64-rpi4.raw.zst
- Release includes both platforms with updated notes
- README updated for dual-platform support