refactor(events): expand eventType taxonomy with central config

Replaces the four-value enum (community/workshop/social/showcase) with
seven values: talk, workshop, community-meetup, coworking, peer-session,
skills-share, info-session. Default is now community-meetup.

Adds app/config/eventTypes.js as the single source of truth for value→label
mapping. Updates the model enum, seed scripts, and admin event list/filter
+ admin dashboard to read from it via EVENT_TYPES and eventTypeLabel().

app/pages/admin/index.vue

@@ -91,7 +91,7 @@
                 <span class="item-sub">{{ formatDateTime(event.startDate) }}</span>
               </div>
               <div class="item-meta">
-                <span class="badge" :class="event.eventType">{{ event.eventType }}</span>
+                <span class="badge" :class="event.eventType">{{ eventTypeLabel(event.eventType) }}</span>
                 <span class="item-date">{{ event.location || 'Online' }}</span>
               </div>
             </div>
@@ -106,6 +106,8 @@
 </template>
 
 <script setup>
+import { eventTypeLabel } from '~/config/eventTypes'
+
 definePageMeta({
   layout: 'admin',
   middleware: 'admin',