chore: checkpoint ai search comments and i18n foundation

backend/assets/views/admin/site_settings.html

@@ -5,7 +5,7 @@
     <div class="table-head">
         <div>
             <h2>站点资料</h2>
-            <div class="table-note">保存后首页、关于页、页脚和友链页中的本站信息会直接读取这里的配置。</div>
+            <div class="table-note">保存后首页、关于页、页脚和友链页中的本站信息会直接读取这里的配置。AI 问答也在这里统一开启和配置。</div>
         </div>
     </div>
 
@@ -74,11 +74,54 @@
             <label>技术栈（每行一个）</label>
             <textarea name="tech_stack">{{ form.tech_stack }}</textarea>
         </div>
+
+        <div class="field field-wide" style="border-top: 1px solid rgba(148, 163, 184, 0.18); padding-top: 18px; margin-top: 10px;">
+            <label style="display:flex; align-items:center; gap:10px;">
+                <input type="checkbox" name="ai_enabled" {% if form.ai_enabled %}checked{% endif %}>
+                <span>启用前台 AI 问答</span>
+            </label>
+            <div class="field-hint">关闭后，前台导航不会显示 AI 页面，公开接口也不会对外提供回答。Embedding 已改为后端本地生成，并使用 PostgreSQL 的 pgvector 存储与检索。</div>
+        </div>
+        <div class="field">
+            <label>聊天 Provider</label>
+            <input name="ai_provider" value="{{ form.ai_provider }}" placeholder="newapi">
+        </div>
+        <div class="field">
+            <label>聊天 API Base</label>
+            <input name="ai_api_base" value="{{ form.ai_api_base }}" placeholder="http://localhost:8317/v1">
+        </div>
         <div class="field field-wide">
+            <label>聊天 API Key</label>
+            <input name="ai_api_key" value="{{ form.ai_api_key }}" placeholder="your-api-key-1">
+            <div class="field-hint">这里只保存在后端数据库里，前台公开接口不会返回这个字段。当前默认接入本地 NewAPI 网关，未配置时前台仍可做本地检索，但不会生成完整聊天回答。</div>
+        </div>
+        <div class="field">
+            <label>聊天模型</label>
+            <input name="ai_chat_model" value="{{ form.ai_chat_model }}" placeholder="gpt-5.4">
+        </div>
+        <div class="field">
+            <label>本地 Embedding</label>
+            <input value="{{ form.ai_local_embedding }}" disabled>
+        </div>
+        <div class="field">
+            <label>Top K</label>
+            <input type="number" min="1" max="12" name="ai_top_k" value="{{ form.ai_top_k }}">
+        </div>
+        <div class="field">
+            <label>Chunk Size</label>
+            <input type="number" min="400" max="4000" step="50" name="ai_chunk_size" value="{{ form.ai_chunk_size }}">
+        </div>
+        <div class="field field-wide">
+            <label>系统提示词</label>
+            <textarea name="ai_system_prompt">{{ form.ai_system_prompt }}</textarea>
+        </div>
+        <div class="field field-wide">
+            <div class="table-note">AI 索引状态：已索引 {{ form.ai_chunks_count }} 个片段，最近建立时间 {{ form.ai_last_indexed_at }}。</div>
             <div class="actions">
                 <button type="submit" class="btn btn-primary">保存设置</button>
+                <button type="button" id="reindex-btn" class="btn">重建 AI 索引</button>
             </div>
-            <div class="field-hint" style="margin-top: 10px;">保存后可直接点击顶部“预览首页 / 预览关于页 / 预览友链页”确认前台展示。</div>
+            <div class="field-hint" style="margin-top: 10px;">文章内容变化后建议手动重建一次 AI 索引。本地 embedding 使用后端内置 `fastembed` 生成，向量会写入 PostgreSQL 的 `pgvector` 列，并通过 HNSW 索引做相似度检索；聊天回答默认走 `newapi -> /responses -> gpt-5.4`。</div>
             <div id="notice" class="notice"></div>
         </div>
     </form>
@@ -89,12 +132,18 @@
 <script>
     const form = document.getElementById("site-settings-form");
     const notice = document.getElementById("notice");
+    const reindexBtn = document.getElementById("reindex-btn");
 
     function showNotice(message, kind) {
         notice.textContent = message;
         notice.className = "notice show " + (kind === "success" ? "notice-success" : "notice-error");
     }
 
+    function numericOrNull(value) {
+        const parsed = Number(value);
+        return Number.isFinite(parsed) ? parsed : null;
+    }
+
     form?.addEventListener("submit", async (event) => {
         event.preventDefault();
 
@@ -118,7 +167,15 @@
             techStack: String(data.get("tech_stack") || "")
                 .split("\n")
                 .map((item) => item.trim())
-                .filter(Boolean)
+                .filter(Boolean),
+            aiEnabled: data.get("ai_enabled") === "on",
+            aiProvider: data.get("ai_provider"),
+            aiApiBase: data.get("ai_api_base"),
+            aiApiKey: data.get("ai_api_key"),
+            aiChatModel: data.get("ai_chat_model"),
+            aiTopK: numericOrNull(data.get("ai_top_k")),
+            aiChunkSize: numericOrNull(data.get("ai_chunk_size")),
+            aiSystemPrompt: data.get("ai_system_prompt")
         };
 
         try {
@@ -134,10 +191,34 @@
                 throw new Error(await response.text() || "save failed");
             }
 
-            showNotice("站点信息已保存。", "success");
+            showNotice("站点信息与 AI 配置已保存。", "success");
         } catch (error) {
             showNotice("保存失败：" + (error?.message || "unknown error"), "error");
         }
     });
+
+    reindexBtn?.addEventListener("click", async () => {
+        reindexBtn.disabled = true;
+        reindexBtn.textContent = "正在重建...";
+
+        try {
+            const response = await fetch("/api/ai/reindex", {
+                method: "POST"
+            });
+
+            if (!response.ok) {
+                throw new Error(await response.text() || "reindex failed");
+            }
+
+            const data = await response.json();
+            showNotice(`AI 索引已重建，当前共有 ${data.indexed_chunks} 个片段。`, "success");
+            window.setTimeout(() => window.location.reload(), 900);
+        } catch (error) {
+            showNotice("重建失败：" + (error?.message || "unknown error"), "error");
+        } finally {
+            reindexBtn.disabled = false;
+            reindexBtn.textContent = "重建 AI 索引";
+        }
+    });
 </script>
 {% endblock %}