fix: contextual logging, word merge overlap resolver, and responsive toolbar/footer UI

Fix focus mode: correctly hide sidebar panels and allow footer to be hoverable to exit focus mode

FIX-33b: Protect second+third preposition regexes with blocklist

Audit fixes: narrow FIX-35 suffixes, raise FIX-37 threshold, remove duplicate sort

Add test suite for FIX-33 through FIX-37 (29 tests)