Fix doxygen pre-existing errors: 41 → 0
- Replace em-dash (—) with -- in ui group description
(doxygen 1.17.0 parser tripped on multi-byte chars near the @dot block)
- Fix @ref kleidos::totp / @ref kleidos::crypto in totp group
(namespaces are not @ref-resolvable; use the @defgroup id instead)
- Replace @ref LvglVaultScreen et al with @c LvglVaultScreen
(LVGL screen classes don't resolve via @ref; @c is correct for
inline code references)
Result: 41 doxygen errors → 0. doxygen Doxyfile exits 0.