tabs.rs had grown to 538 lines — past the 500-line ceiling — and was
mixing four unrelated concerns:
- `tab_navigation` (URL changes + history back/forward)
- `tab_metadata` (title, favicon, zoom, favorite/pin, sort, sync flag)
- `tab_archive_restore` (un-archive entry points + query matching)
- core CRUD (open / close / move-to-space + private helpers)
Each split file lives below 250 lines and only pulls the `ely_domain`
types and crate helpers it actually uses. `active_tab_mut` and the
`TabUrlUpdate` enum get `pub(super)` so siblings can reach them; no
behaviour change.
ZacharyZhang-NY
db7cd2f9bc