Fix author detection for compact dotted names (#4229)

[Hrithikcrick]

Fixes #4229

Summary

Fixes author detection for compact dotted author declarations such as:

Author:Frankie.Chu

The implementation is intentionally scoped to author-tag context so unrelated dotted tokens are not globally classified as names.

Changes

• Normalize compact Author: declarations before tokenization.
• Handle dotted names only when they follow an Author tag.
• Avoid the broader global dotted-name lexer rule that caused unrelated license-validation regressions.
• Add regression coverage for the exact case reported in Author not detected in C++ file #4229.

Testing

• Targeted author regression test: passed.
• Basic copyright detection tests: passed.
• Previously failing license-validation shards: 14,989 passed.
• Full hosted Azure pipeline: passed with 0 errors.
• ReadTheDocs: passed.
• git diff --check: clean.

Files changed

• src/cluecode/copyrights.py
• tests/cluecode/test_copyrights_basic.py

[Hrithikcrick]

Updated after CI validation: the broad dotted-name lexer behavior was removed and the handling is now scoped to Author context.

The previously failing license-validation shards pass locally, the full Azure build now succeeds with 0 errors, and ReadTheDocs is green.

The remaining GitHub Actions workflows are awaiting maintainer approval.

Ready for review. Thanks!