Task #340: center the Time and Actions columns in the Manage table

User feedback (RTL screenshot): the "إجراءات" header and its three
icon buttons were stuck against the far edge of the column, away
from the new vertical divider added in #337; the "الوقت" header
also sat against the start edge while the short "1:55 — 2:05"
value floated separately, so they didn't visually line up.

- Switches both the Time and Actions header cells from
  `text-start` / `text-end` to `text-center`.
- Adds `text-center` to the Time data cell so the
  fixed-width "HH:MM — HH:MM" string sits centered under its
  header.
- Switches the Actions data cell from `text-end` to
  `text-center`; the inline-flex button group (edit /
  duplicate / delete) inherits the centering.
- Loading and "no meetings" rows already render the message
  via `colSpan={4}` and a separate empty Actions cell; no
  text alignment change is needed there for visual parity.

Other columns (select-checkbox, #, Meeting) keep their
existing `text-start` so long titles stay flush with their
header label. The vertical divider (#337) and column widths
(w-28 / w-32) remain untouched. No change to data flow,
testids, or other tabs.

`pnpm -C artifacts/tx-os exec tsc --noEmit` clean. Pre-existing
api-server / test workflow failures are unrelated.

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

@@ -5602,8 +5602,8 @@ function ManageSection({
               </th>
               <th className="px-3 py-2 text-start w-12">#</th>
               <th className="px-3 py-2 text-start">{t("executiveMeetings.col.meeting")}</th>
-              <th className="px-3 py-2 text-start w-28">{t("executiveMeetings.col.time")}</th>
-              <th className="px-3 py-2 text-end w-32 border-s border-gray-200">{t("executiveMeetings.common.actions")}</th>
+              <th className="px-3 py-2 text-center w-28">{t("executiveMeetings.col.time")}</th>
+              <th className="px-3 py-2 text-center w-32 border-s border-gray-200">{t("executiveMeetings.common.actions")}</th>
             </tr>
           </thead>
           <tbody>
@@ -5669,10 +5669,10 @@ function ManageSection({
                     }
                   </div>
                 </td>
-                <td className="px-3 py-2 align-middle font-mono text-xs whitespace-nowrap" dir="ltr">
+                <td className="px-3 py-2 align-middle font-mono text-xs whitespace-nowrap text-center" dir="ltr">
                   {formatTime(m.startTime, isRtl ? "ar" : "en")} — {formatTime(m.endTime, isRtl ? "ar" : "en")}
                 </td>
-                <td className="px-3 py-2 align-middle text-end border-s border-gray-200">
+                <td className="px-3 py-2 align-middle text-center border-s border-gray-200">
                   <div className="inline-flex gap-1">
                     <Button
                       size="sm"