feat(ui): 3-tab layout (Admin overview / My dashboard / Training) + Settings page

- App.vue: top tab bar (Admin overview [admin], My dashboard, Training) + Settings icon
- router: / = admin overview, /my/board, /training, /settings; non-admin '/' -> /my/board
- New views: Training.vue (pick ready product group -> personas), MyBoard.vue (win/lose +
  sessions summary), Settings.vue (change email/password, language)
- Backend: allow /api/me/board + /api/chat/sessions for any authenticated user (so the
  My dashboard tab works for admins too), not just 'user' role
- i18n EN/TH keys; rebuilt frontend/dist
Verified: build ok, /api/me/board + /api/chat/sessions + /api/groups all 200 for admin.

frontend/src/views/MyBoard.vue

@@ -0,0 +1,61 @@
+<template>
+  <div>
+    <h2>📊 {{ i18n.t('myDashboard') }}</h2>
+
+    <!-- Win/Lose summary -->
+    <div class="row stat-row" v-if="!loading">
+      <div class="card stat"><span>{{ i18n.t('total') }}</span><strong>{{ total }}</strong></div>
+      <div class="card stat won"><span>{{ i18n.t('won') }}</span><strong>{{ won }}</strong></div>
+      <div class="card stat lost"><span>{{ i18n.t('lost') }}</span><strong>{{ lost }}</strong></div>
+      <div class="card stat"><span>{{ i18n.t('notTried') }}</span><strong>{{ notTried }}</strong></div>
+    </div>
+
+    <div v-if="loading" class="card"><div class="skeleton" style="height:50px"></div></div>
+    <div v-else-if="items.length === 0" class="card empty-state">
+      <strong>No practice yet</strong>
+      <span>Go to Training and try closing a sale with a persona.</span>
+    </div>
+
+    <!-- Recent sessions -->
+    <div v-show="sessions.length" class="card" style="margin-top:20px">
+      <h3 style="margin-top:0">{{ i18n.t('mySessions') }}</h3>
+      <div v-for="s in sessions" :key="s.id" style="display:flex;justify-content:space-between;padding:8px 0;border-bottom:1px solid var(--border)">
+        <span>{{ s.persona_name }}</span>
+        <span class="badge" :class="s.outcome">{{ s.outcome === 'won' ? i18n.t('won') : i18n.t('lost') }}</span>
+      </div>
+    </div>
+  </div>
+</template>
+
+<script setup>
+import { computed, onMounted, ref } from 'vue'
+import { api } from '../api'
+import { i18n } from '../i18n'
+
+const items = ref([])
+const sessions = ref([])
+const loading = ref(true)
+
+const total = computed(() => items.value.length)
+const won = computed(() => items.value.filter((i) => i.my_outcome === 'won').length)
+const lost = computed(() => items.value.filter((i) => i.my_outcome === 'lost').length)
+const notTried = computed(() => items.value.filter((i) => i.my_outcome === 'not_tried').length)
+
+onMounted(async () => {
+  try {
+    items.value = (await api.myBoard()).board || []
+    sessions.value = (await api.mySessions()).sessions || []
+  } finally {
+    loading.value = false
+  }
+})
+</script>
+
+<style scoped>
+.stat-row { gap: 16px; }
+.stat { text-align: center; min-width: 100px; }
+.stat span { display: block; font-size: 12px; color: var(--muted); }
+.stat strong { font-size: 26px; }
+.stat.won strong { color: var(--green); }
+.stat.lost strong { color: var(--red); }
+</style>