Issue #50: Add validation for invalid page separators
- Add detection for en-dash, em-dash, minus sign, and other invalid dash characters in page numbers
- Provide suggested corrections by replacing invalid dashes with standard hyphens
- Return error message when invalid dash characters are detected

Issue #53: Fix capitalization validation with surrounding punctuation
- Add strip_leading_trailing_non_letters() helper function to extract leading/trailing non-alphabetic characters
- Update format_title() to strip punctuation before checking caps.txt, then reapply after adding braces
- Update format_journal_name() with same fix
- Fixes incorrect brace placement like {(BHI}) → ({BHI})

Issue #58: Add MacOS TeXShop/TeX Live setup instructions
- Add new section "MacOS Setup with TeXShop and TeX Live" to README
- Document TeX Live's ~/Library/texmf/ approach for GUI applications
- Explain why environment variables don't work with Mac GUI apps
- Provide step-by-step instructions with symbolic link setup
- Update table of contents with new subsections

- Fix CoppEtal17: Move parenthesis outside braces in booktitle ({(BHI}) → ({BHI}))
- Fix ShinEtal99: Capitalize 'Third' in title
- Fix NokiEtal08: Add braces around Hz unit
- Fix Trei02: Capitalize A and B in year references
- Fix MilsEtal09: Add braces around F in mathematical expression
- Fix TiitEtal93: Add braces around Hz unit
- Fix NeraBilk05: Add braces around Hz unit
- Fix Nied91: Capitalize 'Third' in title

All fixes ensure bibcheck verify passes cleanly.