feat(executive-meetings): replace native window.confirm with in-app AlertDialog (#342)

Native window.confirm exposes the Repl hostname and ignores the app's
RTL/branding. The user (Arabic-speaking) flagged it as visually jarring
inside Executive Meetings.

Changes (artifacts/tx-os/src/pages/executive-meetings.tsx):
- Add a small ConfirmProvider + useConfirm() backed by the existing
  shadcn AlertDialog (`@/components/ui/alert-dialog`). The hook returns
  Promise<boolean> so call sites stay one-liners:
    if (!(await confirm({ message, destructive: true }))) return;
- Single-flight guard: if a second confirm() arrives while the first is
  still pending, the previous Promise resolves to false (no orphaned
  resolvers).
- Mount the provider once around the page (split the default export
  into a thin wrapper + ExecutiveMeetingsPageInner so the inner tree
  can call useConfirm()).
- Centered title + description, destructive-styled confirm button,
  mobile-safe sizing (max-w-md, w-[calc(100%-2rem)], max-h-[90vh],
  overflow-y-auto). Explicit `dir` on AlertDialogContent so the
  portal-rendered dialog always inherits the page's RTL/LTR.
- Footer renders Action first then Cancel: in LTR Confirm sits on the
  left and Cancel on the right; RTL flips automatically (Confirm right,
  Cancel left). Mobile stacks Cancel on top, destructive at the bottom.
- Replace all 5 window.confirm sites:
  1. Schedule single-row delete (deleteMeeting)
  2. Schedule bulk delete
  3. Manage bulk delete
  4. Manage single delete (confirmDelete)
  5. MeetingFormDialog "remove all attendees" (function turned async)
- Add `confirm` to the relevant useCallback deps (deleteMeeting,
  bulk delete) and inject useConfirm() inside ScheduleSection,
  ManageSection, MeetingFormDialog (all rendered inside the provider).
- New i18n keys: executiveMeetings.common.confirm and .confirmTitle in
  both ar.json and en.json (used as default title / non-destructive
  confirm label).

`pnpm -C artifacts/tx-os exec tsc --noEmit` clean. Pre-existing
api-server / test workflow failures are unrelated to this UI change
(also failing before the task started).

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

@@ -1256,7 +1256,9 @@
       "yes": "نعم",
       "no": "لا",
       "all": "الكل",
-      "filter": "تصفية"
+      "filter": "تصفية",
+      "confirm": "تأكيد",
+      "confirmTitle": "تأكيد"
     },
     "manage": {
       "heading": "إدارة الاجتماعات",

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

@@ -1122,7 +1122,9 @@
       "yes": "Yes",
       "no": "No",
       "all": "All",
-      "filter": "Filter"
+      "filter": "Filter",
+      "confirm": "Confirm",
+      "confirmTitle": "Confirm"
     },
     "manage": {
       "heading": "Manage Meetings",

artifacts/tx-os/src/pages/executive-meetings.tsx

@@ -684,13 +684,16 @@ function ConfirmProvider({ children }: { children: ReactNode }) {
               {opts?.message ?? ""}
             </AlertDialogDescription>
           </AlertDialogHeader>
+          {/*
+            Render the confirm/destructive action FIRST in the JSX so
+            that the default `flex-row` (LTR) places it on the left and
+            Cancel on the right (English spec), while in RTL the visual
+            order flips automatically and Confirm sits on the right with
+            Cancel on the left (Arabic spec). On mobile the
+            `flex-col-reverse` from AlertDialogFooter naturally stacks
+            the destructive action at the bottom and Cancel on top.
+          */}
           <AlertDialogFooter className="sm:justify-center gap-2">
-            <AlertDialogCancel
-              data-testid="em-confirm-cancel"
-              onClick={() => settle(false)}
-            >
-              {cancelLabel}
-            </AlertDialogCancel>
             <AlertDialogAction
               data-testid="em-confirm-ok"
               onClick={() => settle(true)}
@@ -702,6 +705,12 @@ function ConfirmProvider({ children }: { children: ReactNode }) {
             >
               {confirmLabel}
             </AlertDialogAction>
+            <AlertDialogCancel
+              data-testid="em-confirm-cancel"
+              onClick={() => settle(false)}
+            >
+              {cancelLabel}
+            </AlertDialogCancel>
           </AlertDialogFooter>
         </AlertDialogContent>
       </AlertDialog>