fix(copyright): improve Bower verification attribution coverage

[mstykow]

Summary

• improve shared comment-attribution author extraction for C-style Written by/Translated by headers, trailing comment closers, and Name (email|url) contact forms uncovered during Bower verification
• verify the remaining Bower scorecard targets with compare-outputs --profile common (jquery/jquery-ui, select2/select2, and jashkenas/backbone) and mark row 39 as verified
• record the three Bower compare runs in docs/BENCHMARKS.md and regenerate docs/benchmarks/scan-duration-vs-files.svg

Issues

• Covers: parser verification scorecard row 39 (Bower)
• Closes:

Scope and exclusions

• Included:
  • compare-run review for jquery/jquery-ui @ eda7aa34fa59d8f764b2164be3e3b7f14639b0db
  • compare-run review for select2/select2 @ 595494a72fee67b0a61c64701cbb72e3121f97b9
  • compare-run review for jashkenas/backbone @ da75718e896e52e84aa1f0411ba67fafcdcf6af3
  • shared author-detection fix and focused regression coverage
  • scorecard and benchmark documentation updates
• Explicit exclusions:
  • no parser-specific Bower manifest behavior changes were needed
  • no force-push or history rewrite

Intentional differences from Python

• Provenant keeps richer Bower package identity in compare output (type=bower|name=...|datasource_id=bower_json) rather than only a bare purl-style package record.
• Provenant preserves more-correct Unicode author normalization where ScanCode degrades names such as Philippe Rathé.

Follow-up work

• Created or intentionally deferred:
  • no follow-up work created from the reviewed Bower targets; remaining compare deltas were triaged as normalization differences or weaker ScanCode-only noise rather than unresolved ScanCode-better regressions

Expected-output fixture changes

• Files changed: none
• Why the new expected output is correct: the shared author-detection change is covered by focused unit tests plus the test_golden_authors golden suite, and it did not require any parser .expected.json or golden YAML updates.

Compare-run artifacts

• .provenant/compare-runs/20260422T221713Z-jquery-ui-93350
• .provenant/compare-runs/20260422T222307Z-select2-925
• .provenant/compare-runs/20260422T222803Z-backbone-8407