odb: Validate 3dbv region coordinate count (#10460)

[KMohnishM]

Summary

Enforce and validate coordinate count when parsing 3dbv regions in DbvParser::parseRegion.

• Validates that the coords node is present on a region (logs ODB-0521 if missing).
• Ensures that exactly 4 coordinates are defined (representing a standard rectangular bounding box).
• Emits a clean error if the coordinate count is incorrect, including a specific note if the count is > 4 stating that polygonal regions are not yet supported.
• Fixes the existing test (example.3dbv and golden file write_3dbv.3dbvok) where front_reg lacked coordinates.
• Adds new integration tests (example_no_coords.3dbv and example_polygon.3dbv) to prevent future regressions.

Type of Change

• Bug fix
• New feature

Impact

Attempts to load a 3dbv file containing a region with missing or polygonal coordinates will now fail immediately with a clean error message (ODB-0521) rather than propagating uninitialized bounding boxes.

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 included tests to prevent regressions.
• I have signed my commits (DCO).

Related Issues

Closes #10460

[gemini-code-assist]

Code Review

This pull request introduces validation for 3DBV region coordinates, ensuring they are specified and contain exactly four coordinates, as polygonal regions are not yet supported. It also adds corresponding test cases to verify these validation errors. The review feedback correctly identifies a bug in the new Tcl test script where exact string matching is used on the error message, which will cause the tests to fail because the error message contains additional formatting. Using regexp to match the error ID is recommended.

[github-actions]

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• CI passes
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[maliberty]

Thanks for contributing. odb.write_3dbv.tcl is failing.

[maliberty]

This looks like a mistakenly added whitespace.

[KMohnishM]

Thanks for the review @maliberty ! I have cleaned up the trailing whitespace/newlines in write_3dbv.3dbvok to match master's formatting.

I also formatted the Bazel BUILD file with buildifier to resolve the failing lint check and addressed the code review feedback by using regexp in read_3dbv_fail.tcl. Everything should compile and pass successfully now.