feat(admin/members): mark-as-Slack-invited button + date display

Replaces the placeholder Slack-invite handler with a call to the new
PATCH /api/admin/members/:id/slack-status endpoint. Status labels are
reworded to match reality (no Slack API call from this app):

- Pending → Not yet invited
- Invited → Invited <slackInvitedAt>
- Action button copy → 'Mark as Slack invited'
- Removes slackInviteStatus reads from the member detail page (the
  remaining repo-wide sweep lands in the cleanup task).

app/pages/admin/members/[id].vue

@@ -39,11 +39,11 @@
             <form class="edit-form" @submit.prevent="submitEdit">
               <div class="field">
                 <label>Name</label>
-                <input v-model="form.name" type="text" required />
+                <input v-model="form.name" type="text" required >
               </div>
               <div class="field">
                 <label>Email</label>
-                <input v-model="form.email" type="email" required />
+                <input v-model="form.email" type="email" required >
               </div>
               <div class="field">
                 <label>Circle</label>
@@ -106,8 +106,19 @@
               </div>
               <div class="meta-row">
                 <dt>Slack invite</dt>
-                <dd :class="member.slackInvited ? 'status-ok' : 'status-dim'">
-                  {{ member.slackInvited ? "Invited" : "Pending" }}
+                <dd v-if="member.slackInvited" class="status-ok">
+                  Invited {{ formatDate(member.slackInvitedAt) }}
+                </dd>
+                <dd v-else class="meta-action">
+                  <span class="status-dim">Not yet invited</span>
+                  <button
+                    type="button"
+                    class="link-btn"
+                    :disabled="markingSlackInvited"
+                    @click="markSlackInvited"
+                  >
+                    {{ markingSlackInvited ? "Marking…" : "Mark as Slack invited" }}
+                  </button>
                 </dd>
               </div>
               <div v-if="member.helcimCustomerId" class="meta-row">
@@ -155,12 +166,6 @@
                   {{ member.onboarding?.completedAt ? formatDate(member.onboarding.completedAt) : 'In progress' }}
                 </dd>
               </div>
-              <div class="meta-row">
-                <dt>Slack status</dt>
-                <dd :class="slackStatusClass">
-                  {{ member.slackInviteStatus || 'none' }}
-                </dd>
-              </div>
             </dl>
           </section>
 
@@ -356,12 +361,31 @@ const hasBoardEngaged = computed(() => {
   )
 })
 
-const slackStatusClass = computed(() => {
-  const status = member.value?.slackInviteStatus
-  if (status === 'joined') return 'status-ok'
-  if (status === 'invited') return 'status-dim'
-  return 'status-dim'
-})
+const markingSlackInvited = ref(false)
+
+async function markSlackInvited() {
+  if (!member.value || markingSlackInvited.value) return
+  markingSlackInvited.value = true
+  try {
+    const res = await $fetch(
+      `/api/admin/members/${route.params.id}/slack-status`,
+      {
+        method: "PATCH",
+        body: { slackInvited: true },
+      },
+    )
+    member.value = { ...member.value, ...res.member }
+    toast.add({ title: "Marked as Slack invited", color: "success" })
+  } catch (err) {
+    toast.add({
+      title: "Failed to mark Slack invited",
+      description: err.data?.statusMessage || err.message,
+      color: "error",
+    })
+  } finally {
+    markingSlackInvited.value = false
+  }
+}
 
 // Activity log
 const activityEntries = ref([])
@@ -553,6 +577,32 @@ onMounted(loadActivity)
   word-break: break-all;
 }
 
+.meta-action {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  flex-wrap: wrap;
+}
+
+.link-btn {
+  background: none;
+  border: none;
+  color: var(--candle);
+  cursor: pointer;
+  font-family: "Commit Mono", monospace;
+  font-size: 11px;
+  padding: 2px 6px;
+}
+
+.link-btn:hover {
+  text-decoration: underline;
+}
+
+.link-btn:disabled {
+  opacity: 0.6;
+  cursor: not-allowed;
+}
+
 .mono {
   font-family: "Commit Mono", monospace;
   font-size: 11px;