Root cause: whole tab was draggable=true, so a click with any micro-movement
became a (no-op) drag instead of a click → switch failed. Plus every event
(activity/title/status) rebuilt the entire tab bar via replaceChildren, which
could destroy the element mid-click.
Fix:
- switch on pointerdown (fires before drag arms; also works on touch)
- build tab DOM once; update classes/dot/label IN PLACE (refreshTab); full
rebuild only on structural change (add/close/reorder/rename)
- close/rename-input stopPropagation on pointerdown so they don't re-activate
Verified: single pointerdown/click switches reliably across tabs; rename + drag
still work. 198 tests green.
e058751962