feat: add MCP/skill tool protocol, tasks/tools pages, chat UX overhaul

Tools page: skill & MCP server management with [[skill:]]/[[mcp:]] protocol (up to 3 rounds). New Tasks and Tools pages. Chat: session snapshots, empty-session reuse, per-message model_id, unified JSON prediction suggestions. Settings: upload size limit, prediction options, model enable/disable. Schema additions with ensure_column migrations. Add FEATURES/ARCHITECTURE docs.

ui/src/pages/SettingsPage.tsx

@@ -1,20 +1,40 @@
-import { useEffect, useState } from "react";
+import { useEffect, useRef, useState } from "react";
 import { api, AppInfo } from "../api";
 
 export default function SettingsPage() {
   const [info, setInfo] = useState<AppInfo | null>(null);
   const [settings, setSettings] = useState<Record<string, string>>({});
+  const [recommendDirDraft, setRecommendDirDraft] = useState("");
+  const [uploadMsg, setUploadMsg] = useState<string | null>(null);
+  const uploadInputRef = useRef<HTMLInputElement>(null);
 
   useEffect(() => {
     api.appInfo().then(setInfo);
     api.settingsGet().then(setSettings);
   }, []);
 
+  useEffect(() => {
+    setRecommendDirDraft(settings.recommend_dir ?? "");
+  }, [settings.recommend_dir]);
+
   async function handleSave(key: string, value: string) {
     await api.settingsSet(key, value);
     setSettings((prev) => ({ ...prev, [key]: value }));
   }
 
+  async function handleUpload(file: File) {
+    setUploadMsg(null);
+    try {
+      const text = await file.text();
+      await api.importRecommendations(file.name, text);
+      setUploadMsg(`已导入 ${file.name}`);
+    } catch (e) {
+      setUploadMsg(String(e));
+    } finally {
+      if (uploadInputRef.current) uploadInputRef.current.value = "";
+    }
+  }
+
   return (
     <div className="h-full overflow-auto p-6">
       <h1 className="text-xl font-semibold">设置</h1>
@@ -85,6 +105,131 @@ export default function SettingsPage() {
           </div>
         </div>
 
+        <div className="rounded-xl border border-border bg-panel p-5">
+          <div className="text-xs uppercase text-slate-400">对话</div>
+          <div className="mt-3 flex items-center justify-between rounded-lg border border-border bg-panel-2 px-3 py-2.5">
+            <div>
+              <div className="text-sm">自动生成对话标题</div>
+              <div className="mt-0.5 text-xs text-slate-400">
+                首次对话生成回复后，自动为会话生成标题并覆盖
+              </div>
+            </div>
+            <Toggle
+              checked={settings.auto_title !== "false"}
+              onChange={(checked) =>
+                handleSave("auto_title", checked ? "true" : "false")
+              }
+            />
+          </div>
+          <div className="mt-3 flex items-center justify-between rounded-lg border border-border bg-panel-2 px-3 py-2.5">
+            <div>
+              <div className="text-sm">自动预测用户接下来说的话</div>
+              <div className="mt-0.5 text-xs text-slate-400">
+                大模型回答完成后自动预测几条用户可能要说的话，点击即可填入输入框
+              </div>
+            </div>
+            <Toggle
+              checked={settings.suggest_enabled !== "false"}
+              onChange={(checked) =>
+                handleSave("suggest_enabled", checked ? "true" : "false")
+              }
+            />
+          </div>
+          <div className="mt-3">
+            <SettingInput
+              label="预测条数（1-5）"
+              value={settings.suggest_count ?? "3"}
+              onSave={(v) => {
+                const n = Math.max(1, Math.min(5, Number(v) || 3));
+                handleSave("suggest_count", String(n));
+              }}
+            />
+          </div>
+        </div>
+
+        <div className="rounded-xl border border-border bg-panel p-5">
+          <div className="text-xs uppercase text-slate-400">推荐模型列表</div>
+          <div className="mt-3 space-y-3">
+            <div>
+              <span className="text-xs text-slate-400">
+                JSON 文件目录（软件自带默认列表，上传的 JSON 也会保存到这里）
+              </span>
+              <div className="mt-1 flex gap-2">
+                <input
+                  className="input flex-1"
+                  value={recommendDirDraft}
+                  onChange={(e) => setRecommendDirDraft(e.target.value)}
+                />
+                <button
+                  className="btn-secondary"
+                  onClick={() => handleSave("recommend_dir", recommendDirDraft)}
+                  disabled={recommendDirDraft === settings.recommend_dir}
+                >
+                  保存
+                </button>
+                <button
+                  className="btn-secondary"
+                  onClick={() =>
+                    recommendDirDraft && api.openPath(recommendDirDraft)
+                  }
+                >
+                  打开
+                </button>
+              </div>
+            </div>
+            <div className="flex items-center gap-2">
+              <input
+                ref={uploadInputRef}
+                type="file"
+                accept=".json"
+                className="hidden"
+                onChange={(e) => {
+                  if (e.target.files && e.target.files.length > 0) {
+                    handleUpload(e.target.files[0]);
+                  }
+                }}
+              />
+              <button
+                className="btn-secondary"
+                onClick={() => uploadInputRef.current?.click()}
+              >
+                上传 JSON
+              </button>
+              <span className="text-xs text-slate-500">
+                可上传多个推荐列表 JSON，同名文件将覆盖
+              </span>
+            </div>
+            {uploadMsg ? (
+              <div className="text-xs text-slate-400">{uploadMsg}</div>
+            ) : null}
+            <div className="text-xs text-slate-500">JSON 格式示例：</div>
+            <pre className="mt-1 overflow-x-auto rounded-lg bg-panel-2 p-2 text-[11px] leading-relaxed text-slate-400">
+              {`{
+  "models": [
+    {
+      "id": "Qwen/Qwen2.5-7B-Instruct-GGUF",
+      "source": "huggingface",
+      "params": "7B",
+      "architecture": "dense",
+      "vision": false,
+      "files": [
+        {
+          "path": "xx-q4_k_m.gguf",
+          "quant": "Q4_K_M",
+          "size_gb": 4.68,
+          "links": [
+            "https://hf-mirror.com/Qwen/Qwen2.5-7B-Instruct-GGUF/resolve/main/xx-q4_k_m.gguf",
+            "https://modelscope.cn/models/Qwen/Qwen2.5-7B-Instruct-GGUF/resolve/master/xx-q4_k_m.gguf"
+          ]
+        }
+      ]
+    }
+  ]
+}`}
+            </pre>
+          </div>
+        </div>
+
         <div className="text-xs text-slate-500">
           获取 llama-server：运行 <code className="text-slate-300">scripts/fetch-llama.ps1</code>{" "}
           自动下载预编译引擎，或手动指定已下载的 exe 路径。
@@ -94,6 +239,32 @@ export default function SettingsPage() {
   );
 }
 
+function Toggle({
+  checked,
+  onChange,
+}: {
+  checked: boolean;
+  onChange: (checked: boolean) => void;
+}) {
+  return (
+    <button
+      type="button"
+      role="switch"
+      aria-checked={checked}
+      onClick={() => onChange(!checked)}
+      className={`relative h-6 w-11 shrink-0 rounded-full transition-colors ${
+        checked ? "bg-accent" : "bg-panel-2"
+      }`}
+    >
+      <span
+        className={`absolute top-0.5 h-5 w-5 rounded-full bg-white shadow transition-all ${
+          checked ? "left-[22px]" : "left-0.5"
+        }`}
+      />
+    </button>
+  );
+}
+
 function SettingInput({
   label,
   value,