Task #192: Show row color + merge range previews in row-actions kebab menu

Original task: The Executive Meetings row-actions kebab menu has three sub-views
(delete, color, merge). Users couldn't tell at a glance which colour or merge
range a row already had — they had to drill into the sub-view first. Add subtle
inline indicators to the main menu so the current state is visible without
extra clicks.

Implementation:
- artifacts/tx-os/src/pages/executive-meetings.tsx
  • RowActionsMenu now renders an inline circular swatch next to the "Row
    color" item, reflecting the row's saved colour. "default" shows a hatched
    pattern matching the swatch picker; other keys show the saved tint.
    Decorative (aria-hidden) since the swatch sub-view is the actual control.
    Carries data-testid="em-row-color-indicator-{id}" plus a data-color-key
    attribute for stable, language-agnostic tests.
  • Renders a "Merged: <cols>" badge next to the "Merge cells" item only when
    the row has a stored merge. Column names come from the canonical merge
    order (number, meeting, attendees, time) and are localized via the
    existing executiveMeetings.col.{id} keys.
  • New mergeColumnLabels prop is computed in MeetingRow against
    CANONICAL_MERGE_ORDER (not visibleColumns) so the badge still describes
    the full saved range when a boundary column is hidden. Threaded into
    both call sites — the first-visible-cell anchor and the merged-cell
    anchor.
  • Widened the local t prop type to (k, opts?) so the badge can use the
    {{cols}} interpolation template.

- artifacts/tx-os/src/locales/en.json + ar.json
  • Added executiveMeetings.merge.activeBadge ("Merged: {{cols}}" /
    "مدموج: {{cols}}").

Tests:
- Added artifacts/tx-os/tests/executive-meetings-row-actions-previews.spec.mjs
  with two specs:
    1. Row-color indicator updates from "default" → "red" → "default" via the
       sub-view picker, and the dot's computed background tracks the saved
       colour (#fee2e2 → rgb(254,226,226)).
    2. Plain rows render no merge badge; merged rows render the badge with
       text "<MeetingColLabel> + <AttendeesColLabel>". Column labels are
       resolved from the live header DOM so the assertion works in both
       English and Arabic (admin's preferredLanguage overrides the
       tx-lang=en init seed after login).
  Both pass; existing executive-meetings-row-actions-menu.spec.mjs and
  executive-meetings-merge.spec.mjs continue to pass (5/5 regression).

Notable subtleties:
- A first attempt at the merge spec hit a flake where Escape-then-force-click
  on the next row's kebab landed on the previous popover's Delete item
  (which was still mounted), triggering a stray confirm dialog. Added an
  explicit waitFor on the previous popover's unmount before opening the
  next one.

Follow-up proposed: #276 (next_steps) — show the same cues directly on the
row itself, not only inside the kebab popover.

Replit-Task-Id: 7ff92dcd-f4bd-421d-93c8-4d7d3dbe0077

artifacts/tx-os/src/locales/ar.json

@@ -1118,7 +1118,8 @@
       "meetingAttendees": "دمج الاجتماع + الحضور",
       "meetingTime": "دمج الاجتماع + الحضور + الوقت",
       "all": "دمج الصف بالكامل",
-      "unmerge": "إلغاء الدمج"
+      "unmerge": "إلغاء الدمج",
+      "activeBadge": "مدموج: {{cols}}"
     },
     "nav": {
       "schedule": "جدول الاجتماعات اليومي",