Add unicode normalization for word indexing (v0.36.10)

- Add unicode_normalize.go with mappings for small caps and fraktur
- Map 77 decorative unicode characters to ASCII equivalents:
  - Small caps (25 chars): ᴅᴇᴀᴛʜ → death
  - Fraktur lowercase (26 chars): 𝔡𝔢𝔞𝔱𝔥 → death
  - Fraktur uppercase (26 chars): 𝔇𝔈𝔄𝔗ℌ → death
- Fix broken utf8DecodeRuneInString() that failed on multi-byte UTF-8
- Add migration v7 to rebuild word indexes with normalization
- Add comprehensive unit tests for all character mappings

Files modified:
- pkg/database/unicode_normalize.go: New - character mapping tables
- pkg/database/unicode_normalize_test.go: New - unit tests
- pkg/database/tokenize.go: Integrate normalizeRune(), fix UTF-8 decoder
- pkg/database/migrations.go: Add version 7 migration

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

pkg/version/version

@@ -1 +1 @@
-v0.36.9
+v0.36.10