dbSta: check cross-layer pin alignment

[mahjiid]

Summary

Extends check_ip LEF-CHK-003 so it can detect when minimum-width signal pins on different routing layers cannot be aligned to their track grids with one shared macro translation.

The existing check validates each layer independently. This adds the cross-layer constraint discussed in #4872 and in the review thread from #9405.

Implementation

• Keep the existing per-layer effective-pitch/GCD validation.
• Derive the required macro-translation congruence for each checked routing layer.
• Compare layers that constrain the same placement axis using the generalized Chinese Remainder compatibility condition.
• Report a warning when no single translation can satisfy both layers.
• Add a focused LEF/DEF/Tcl regression with one compatible and one impossible multi-layer case.
• Register the regression in both Bazel and CMake.

Validation

• git diff --check passes.
• Commit includes DCO sign-off.
• Focused regression is registered for CI.
• A full local OpenROAD build was not run because this Windows machine does not currently have the project Bazel/C++ toolchain installed; CI should exercise the registered test.

Part of #4872

[gemini-code-assist]

Code Review

This pull request enhances the IP checker's pin routing grid alignment check (LEF-CHK-003) to include cross-layer compatibility verification. It introduces a new LayerAlignmentConstraint structure and applies the Chinese Remainder Theorem to ensure that a single macro translation can simultaneously satisfy alignment constraints across multiple routing layers on the same placement axis. Additionally, a new pass/fail test case check_ip_multilayer_alignment has been added to validate this cross-layer alignment logic. There are no review comments, and I have no feedback to provide.

[github-actions]

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