feat: 优化 Chat 页面和 Agents 页面

- 优化 Chat 页面交互和消息显示
- 增强 Agents 页面功能
- 改进 ChatAgentSelector 组件
- 优化 ChatMessage 和 ChatSidebar 组件
- 更新聊天逻辑 useAgents 和 chat 模块

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web/src/views/agents/useAgents.ts

@@ -278,7 +278,7 @@ async function createAgent() {
     const skillsLabels = newAgent.value.selectedSkills.map(id => getSkillLabel(id)).join(', ')
 
     agents.value.unshift({
-      id: result.agent_id,
+      id: result.agent_id_str || result.agent_id,
       name: newAgent.value.name,
       avatar: newAgent.value.avatar,
       description: newAgent.value.description,
@@ -341,6 +341,7 @@ async function saveEdit() {
       body: JSON.stringify({
         name: editingAgent.value.name,
         description: editingAgent.value.description,
+        avatar: editingAgent.value.avatar,
         skills: skills,
         role_description: editingAgent.value.prompt,
         model_provider: selectedModel?.provider || '',
@@ -353,6 +354,7 @@ async function saveEdit() {
       if (agent) {
         agent.name = editingAgent.value.name
         agent.description = editingAgent.value.description
+        agent.avatar = editingAgent.value.avatar
         agent.skills = editingAgent.value.skillsMode === 'all' ? '*' : editingAgent.value.selectedSkills.join(', ')
         agent.model = selectedModel?.name || ''
       }