MC-4775

User report from Telegram with mobile screenshot: Board v2 on phone still has no easy way to switch between Inbox and Todo. Current visible mobile state shows Inbox heading/count and cards, but no obvious Inbox/Todo/Done segmented control or lane switcher above the list. Scope: - Add an obvious mobile-friendly status switcher for Inbox / Todo / Done (or equivalent) on Board v2. - It must be visible without horizontal scrolling and should not rely on the legacy board link. - Preserve existing card actions: Start, Not needed, Done where safe. - After Start / Not needed / Done, the current view should update immediately: card moves/disappears, counts/tabs sync, no manual refresh. - Preserve/verify mobile swipe actions where applicable: left = Start, right = Not needed/Cancel, with accessible button fallbacks. - Fix related mobile overflow/clipping if the switcher or board controls exceed viewport width. Acceptance gate: - Regression coverage for tab/status filtering, count sync, post-action local update, and safe Done visibility rules. - Live 375px browser smoke on the same URL class Elmar opens. - Fresh mobile screenshots for initial Inbox/Todo switcher and post-action state. - Browser console clean after taps/swipes. - Do not use real user work for destructive-ish action tests; use safe fixtures or controlled test tickets. Source evidence: Telegram screenshot at /home/lucienne/.hermes/image_cache/img_d5120f57cebe.jpg and user comment: "We still don't have an easy way to switch between inbox and todo."