Name Sanitization

All user-provided names (theme, entities, colors, modes) are sanitized before being used in Figma variable paths and collection names. The sanitizeName() function applies these transformations:

1. Cyrillic transliteration -- а → a, б → b, ж → zh, щ → sch, etc. Full Russian alphabet supported.
2. Lowercase -- "My Surface" → "my surface"
3. Spaces → hyphens -- "my surface" → "my-surface"
4. Remove invalid characters -- only a-z, 0-9, -, _, / survive
5. Collapse hyphens -- "a---b" → "a-b"
6. Trim hyphens -- no leading/trailing hyphens

Examples:

Input	Sanitized
"Surfaces"	surfaces
"Content on Layers"	content-on-layers
"Фон (основной)"	fon-osnovnoy
"UI / Brand"	ui/brand
"--Hello World--"	hello-world

Duplicate detection also uses sanitizeName() -- two names that sanitize to the same string are flagged as duplicates (e.g., "My Color" and "my-color").

---