feat: add game library CRUD/import/export/favorites/comments, fix team creation

- Game library: add/delete games per group, JSON/CSV import/export, favorites, star ratings & comments
- Fix team session creation: add creator to members array, handle null currentGroup
- Fix image loading: rename SVG files from .png to .svg extensions
- Add PocketBase migrations for game_comments and game_favorites collections
- Remove seed data script

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

frontend/src/components/team/GameSelectDialog.vue

@@ -82,7 +82,7 @@ function confirmCustomGame() {
           @click="selectGame(game)"
         >
           <img
-            :src="game.cover || '/game-placeholder.png'"
+            :src="game.cover || '/game-placeholder.svg'"
             :alt="game.name"
             class="game-cover"
           />

frontend/src/components/team/IdleMembersList.vue

@@ -59,7 +59,7 @@ async function inviteMember(userId: string, username: string) {
         class="member-item"
       >
         <img
-          :src="member.avatar || '/default-avatar.png'"
+          :src="member.avatar || '/default-avatar.svg'"
           :alt="member.username"
           class="avatar"
         />

frontend/src/components/team/InvitationCard.vue

@@ -49,7 +49,7 @@ async function rejectInvitation() {
   <div class="invitation-card">
     <div class="invitation-header">
       <img
-        :src="invitation.expand?.from?.avatar || '/default-avatar.png'"
+        :src="invitation.expand?.from?.avatar || '/default-avatar.svg'"
         :alt="invitation.expand?.from?.username"
         class="avatar"
       />

frontend/src/components/team/TeamSessionPanel.vue

@@ -1,16 +1,20 @@
 <!-- src/components/team/TeamSessionPanel.vue -->
 <script setup lang="ts">
-import { computed } from 'vue'
+import { computed, ref } from 'vue'
 import { useTeamStore } from '@/stores/team'
 import { useGroupStore } from '@/stores/group'
+import { useUserStore } from '@/stores/user'
 import { TeamStatusMap } from '@/types'
-import { ElMessageBox } from 'element-plus'
+import { ElMessageBox, ElMessage } from 'element-plus'
+import GameSelectDialog from '@/components/team/GameSelectDialog.vue'
 
 const teamStore = useTeamStore()
 const groupStore = useGroupStore()
+const userStore = useUserStore()
 
 const session = computed(() => teamStore.currentSession)
 const statusText = computed(() => session.value ? TeamStatusMap[session.value.status] : '')
+const showGameSelect = ref(false)
 
 const memberDetails = computed(() => {
   if (!session.value) return []
@@ -43,6 +47,35 @@ async function endGame() {
     // 用户取消
   }
 }
+
+async function handleGameSelected(gameName: string) {
+  let group = groupStore.currentGroup
+  if (!group) {
+    if (groupStore.groups.length > 0) {
+      group = groupStore.groups[0]
+      await groupStore.setCurrentGroup(group.id)
+    } else {
+      ElMessage.warning('请先创建或加入一个群组')
+      return
+    }
+  }
+
+  if (teamStore.currentSession) return
+
+  const userId = userStore.userId
+  try {
+    await teamStore.createSession({
+      sourceGroup: group.id,
+      name: `${gameName} 小队`,
+      gameName,
+      members: [userId]
+    })
+    ElMessage.success('临时小队创建成功！')
+  } catch (error: any) {
+    console.error('创建临时小队失败:', error)
+    ElMessage.error('创建临时小队失败：' + (error.message || '未知错误'))
+  }
+}
 </script>
 
 <template>
@@ -66,7 +99,7 @@ async function endGame() {
           class="member-item"
         >
           <img
-            :src="member.avatar || '/default-avatar.png'"
+            :src="member.avatar || '/default-avatar.svg'"
             :alt="member.username"
             class="avatar"
           />
@@ -87,8 +120,13 @@ async function endGame() {
   </div>
 
   <div v-else class="no-session">
-    <p>暂未加入任何临时小组</p>
+    <p class="no-session-text">暂未加入任何临时小组</p>
+    <button class="create-team-btn" @click="showGameSelect = true">
+      创建临时小队
+    </button>
   </div>
+
+  <GameSelectDialog v-model="showGameSelect" @select="handleGameSelected" />
 </template>
 
 <style scoped>
@@ -251,9 +289,30 @@ async function endGame() {
   background: var(--gg-bg-card);
   border: 1px solid var(--gg-border);
   border-radius: var(--gg-radius-md);
-  padding: 48px 32px;
+  padding: 40px 32px;
   text-align: center;
+}
+
+.no-session-text {
   color: var(--gg-text-muted);
   font-size: 15px;
+  margin: 0 0 20px;
+}
+
+.create-team-btn {
+  padding: 12px 32px;
+  border: none;
+  border-radius: var(--gg-radius-sm);
+  background: var(--gg-gradient-green);
+  color: white;
+  font-size: 15px;
+  font-weight: 600;
+  cursor: pointer;
+  transition: box-shadow 0.3s, transform 0.15s;
+}
+
+.create-team-btn:hover {
+  box-shadow: 0 4px 20px rgba(5, 150, 105, 0.3);
+  transform: translateY(-1px);
 }
 </style>