Second step of the Phase 5 split. The kebab dropdown — including
clickOutside handling and its own mobileMenuOpen state — becomes its
own component named after its visual region. The mobile snippet
duplication inside DocumentTopBar is removed; the component owns its
mobile-specific markup.
TDD: DocumentMobileMenu.svelte.test.ts (7 tests) was red first. The
component then made it green (kebab trigger, dropdown open/close on
click, transcribe button gated on canWrite × isPdf × !transcribeMode,
download link gated on filePath). DocumentTopBar wraps the new
component in a md:hidden div so responsive behaviour is unchanged.
Existing 18-test DocumentTopBar suite still passes.
Refs #496.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
