AutoSubs v3.2.0: short-form punctuation cleanup and word-by-word captions

[GodsQuantum]

Summary

• add one-click removal of sentence-ending full stops in Editor while preserving commas, exclamation/question marks and ellipses
• add one-step undo before saving
• add Word by word animation using canonical word timings
• keep French elisions and split hyphen compounds together (for example l' + amour, rendez- + vous)
• keep preview and ASS/libass render behavior aligned
• bump AutoSubs to v3.2.0

Verification

• 78/78 Rust tests
• cargo fmt --check
• cargo clippy --locked --all-targets --all-features -- -D warnings
• npm audit: 0 vulnerabilities
• 28/28 frontend tests
• svelte-check: 0 errors / 0 warnings
• production frontend build successful