DRT: handle guides below the bottom routing layer

[openroad-ci]

Summary

In a test case, GuidesProcessor generated a long guide below the bottom routing layer which caused a mazerouteError. In this PR, I allow only via guides below the bottom routing layer except for ISPD designs which use long guides on M1.

Type of Change

• Bug fix

Impact

Very minor indirect changes in the final result.

Verification

• I have verified that the local build succeeds (./etc/Build.sh).
• I have run the relevant tests and they pass.
• My code follows the repository's formatting guidelines.
• I have signed my commits (DCO).

[gemini-code-assist]

Code Review

This pull request introduces the DBPROCESSNODE configuration, specifically adding logic to handle 'ISPD' nodes within the guide processing stage. It enables a previously disabled validation check for non-ISPD nodes and adjusts the guide splitting logic to conditionally skip rectangle additions based on the layer and node type. Corresponding test cases have been updated to include the new parameter. A review comment identifies a redundant logical condition in GuideProcessor.cpp that could be simplified for better clarity.

[osamahammad21]

Relevant CI runs:
ISPD: https://jenkins.openroad.tools/blue/organizations/jenkins/OpenROAD-Special-Private/detail/TR-guides-bottom-routing-layer/4/pipeline
ORFS: https://jenkins.openroad.tools/blue/organizations/jenkins/OpenROAD-flow-scripts-Private/detail/secure-TR-guides-bottom--routing-layer/3/pipeline

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"

[maliberty]

Why not change the min routing layer for ispd if there are long guides on m1?

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"

[osamahammad21]

Why not change the min routing layer for ispd if there are long guides on m1?

Done. Shows some improvement in the initial number of DRVs

[maliberty]

I'll leave it to you to clean the CI issues and merge

[osamahammad21]

@sombraSoft @vvbandeira macOS build fails for a download failure:

WARNING: Download from https://github.com/keith/buildifier-prebuilt/releases/download/8.5.1.2/buildifier-prebuilt.8.5.1.2.tar.gz failed: class java.io.IOException GET returned 504 Gateway Time-out
INFO: Repository buildifier_prebuilt+ instantiated at:
  <builtin>: in <toplevel>
Repository rule http_archive defined at:
  /private/var/tmp/_bazel_runner/d729dbc1[76](https://github.com/The-OpenROAD-Project/OpenROAD/actions/runs/24606168224/job/71957315921?pr=10157#step:6:77)423a97322119b43f8d4f13/external/bazel_tools/tools/build_defs/repo/http.bzl:431:31: in <toplevel>
ERROR: /private/var/tmp/_bazel_runner/d729dbc176423a97322119b43f8d4f13/external/bazel_tools/tools/build_defs/repo/http.bzl:156:45: An error occurred during the fetch of repository 'buildifier_prebuilt+':
   Traceback (most recent call last):
	File "/private/var/tmp/_bazel_runner/d729dbc176423a97322119b43f8d4f13/external/bazel_tools/tools/build_defs/repo/http.bzl", line 156, column 45, in _http_archive_impl
		download_info = ctx.download_and_extract(
Error in download_and_extract: java.io.IOException: Error downloading [https://github.com/keith/buildifier-prebuilt/releases/download/8.5.1.2/buildifier-prebuilt.8.5.1.2.tar.gz] to /private/var/tmp/_bazel_runner/d729dbc176423a97322119b43f8d4f13/external/buildifier_prebuilt+/temp17599[81](https://github.com/The-OpenROAD-Project/OpenROAD/actions/runs/24606168224/job/71957315921?pr=10157#step:6:82)6873031144393/buildifier-prebuilt.8.5.1.2.tar.gz: GET returned 504 Gateway Time-out
ERROR: Analysis of target '//:openroad' failed; build aborted: no such package '@@buildifier_prebuilt+//': java.io.IOException: Error downloading [https://github.com/keith/buildifier-prebuilt/releases/download/8.5.1.2/buildifier-prebuilt.8.5.1.2.tar.gz] to /private/var/tmp/_bazel_runner/d729dbc176423a97322119b43f8d4f13/external/buildifier_prebuilt+/temp17599816873031144393/buildifier-prebuilt.8.5.1.2.tar.gz: GET returned 504 Gateway Time-out

[maliberty]

I re-ran it twice and it then passed. Must have been some transient failure on the remote

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"