Redesign the channel tag cell (the popover pilot's first real consumer) to fix two
UAT-reported bugs and two UX gaps:
- Jumping editor (bug 1): the "+" edit trigger now sits in a STABLE slot at the end,
so toggling a tag (which grows the chip row) no longer moves the anchor — the editor
popover stays put (verified dx/dy = 0).
- Whole-table reflow (bug 2): the cell is width-bounded (max-w inside the cell, since
table-layout:auto ignores the column width — the documented channel/About trap) and
single-line, collapsing overflow into a hoverable "+N" pill. Rows no longer wrap and
reflow (verified uniform row heights).
- The "+" is ALWAYS present (even with zero tags), and its menu can CREATE a tag inline
(type + Enter → create + attach) — tagging no longer requires the top-of-page dialog.
New shared ChannelTagsControl (used by table + cards; the detail page is Part 2) over the
R8 popover platform: a `menu` editor popover + a `hover` reveal-all popover. Greedy rem-safe
fit via ResizeObserver. `api.createTag` now returns Promise<Tag>.
peter
cfa8be950d