ci: optimize pipeline with pdk caching and comprehensive artifacts

[anlit75]

Summary

This PR significantly improves the Developer Experience (DX) and CI performance of the ChipForAll template. It addresses the slow pipeline execution times caused by redundant PDK downloads and enhances the post-run debugging capabilities by capturing all relevant build artifacts.

Key Changes

⚡ Performance: PDK Caching

• Implemented actions/cache@v4 in verify.yml to cache the ~3GB Sky130 PDK in the ./pdks directory.
• Impact: Subsequent CI runs (Cache Hits) will bypass the lengthy download phase, reducing the make gds execution time by approximately 5-10 minutes.

📦 Debugging: Comprehensive Artifacts

• Artifact Upload: Modified the upload-artifact step to archive the entire build/ directory instead of just the .gds file.
• Impact: Users downloading the CI artifacts will now receive the full suite of debugging files, including:
  • Final layout (<DESIGN_NAME>.gds)
  • Logic synthesis netlist (synthesis.json)
  • Simulation waveforms (*.vvp / *.vcd)
  • Complete OpenLane logs and routing reports (build/runs/)

[gemini-code-assist]

Note

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