feat: multi-branch template scanning from git repo + manual template selection

- Rewrite template.rs to scan all remote branches via git commands
  (git fetch/branch -r/ls-tree/git show/git archive)
- Add manual template picker dropdown in CreateForm UI
- Remove sentence-transformers/embed.py from Dockerfile (separate container)
- Clean up Gitea API approach, use local git repo instead
- Add chat panel and sidebar layout improvements

web/src/components/CreateForm.vue

@@ -1,20 +1,30 @@
 <script setup lang="ts">
 import { ref, onMounted } from 'vue'
+import { api } from '../api'
 import examples from '../examples.json'
 
 const emit = defineEmits<{
-  submit: [requirement: string]
+  submit: [requirement: string, templateId?: string]
   cancel: []
 }>()
 
 const requirement = ref('')
 const inputEl = ref<HTMLTextAreaElement>()
+const templates = ref<{ id: string; name: string; description: string }[]>([])
+const selectedTemplate = ref('')
 
-onMounted(() => inputEl.value?.focus())
+onMounted(async () => {
+  inputEl.value?.focus()
+  try {
+    templates.value = await api.listTemplates()
+  } catch {
+    // ignore — templates dropdown just won't show
+  }
+})
 
 function onSubmit() {
   const text = requirement.value.trim()
-  if (text) emit('submit', text)
+  if (text) emit('submit', text, selectedTemplate.value || undefined)
 }
 </script>
 
@@ -38,6 +48,13 @@ function onSubmit() {
       @keydown.ctrl.enter="onSubmit"
       @keydown.meta.enter="onSubmit"
     />
+    <div v-if="templates.length" class="template-select">
+      <label>模板</label>
+      <select v-model="selectedTemplate">
+        <option value="">自动选择</option>
+        <option v-for="t in templates" :key="t.id" :value="t.id">{{ t.name }}</option>
+      </select>
+    </div>
     <div class="create-hint">Ctrl+Enter 提交</div>
     <div class="create-actions">
       <button class="btn-cancel" @click="emit('cancel')">取消</button>
@@ -100,6 +117,34 @@ function onSubmit() {
   border-color: var(--accent);
 }
 
+.template-select {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+}
+
+.template-select label {
+  font-size: 13px;
+  color: var(--text-secondary);
+  white-space: nowrap;
+}
+
+.template-select select {
+  flex: 1;
+  padding: 6px 8px;
+  background: var(--bg-secondary);
+  border: 1px solid var(--border);
+  border-radius: 6px;
+  color: var(--text-primary);
+  font-size: 13px;
+  font-family: inherit;
+  outline: none;
+}
+
+.template-select select:focus {
+  border-color: var(--accent);
+}
+
 .create-hint {
   font-size: 12px;
   color: var(--text-secondary);