diff --git a/go/projects/lyra/docs/demo.sql b/go/projects/lyra/docs/demo.sql
new file mode 100644
index 0000000..0f2aa58
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+++ b/go/projects/lyra/docs/demo.sql
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+-- Polaris 导航站 PostgreSQL 新库初始化示例（非幂等，仅执行一次）。
+
+BEGIN;
+
+-- updated_at 维护函数
+CREATE FUNCTION public.set_updated_at()
+RETURNS trigger
+LANGUAGE plpgsql
+AS $$
+BEGIN
+    NEW.updated_at := now();
+    RETURN NEW;
+END;
+$$;
+
+-- 用户表
+CREATE TABLE public.users (
+    id            bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
+    account       text NOT NULL UNIQUE,
+    password_hash text NOT NULL,
+    display_name  text NOT NULL,
+    created_at    timestamptz NOT NULL DEFAULT now(),
+    updated_at    timestamptz NOT NULL DEFAULT now(),
+    CONSTRAINT users_account_not_empty CHECK (btrim(account) <> ''),
+    CONSTRAINT users_display_name_not_empty CHECK (btrim(display_name) <> '')
+);
+
+COMMENT ON TABLE public.users IS '后台管理用户表';
+COMMENT ON COLUMN public.users.id IS '用户 ID';
+COMMENT ON COLUMN public.users.account IS '登录账号，当前大小写敏感';
+COMMENT ON COLUMN public.users.password_hash IS '密码哈希';
+COMMENT ON COLUMN public.users.display_name IS '展示昵称';
+COMMENT ON COLUMN public.users.created_at IS '创建时间';
+COMMENT ON COLUMN public.users.updated_at IS '更新时间，触发器自动刷新';
+
+-- 分类表
+CREATE TABLE public.categories (
+    id          bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
+    slug        text NOT NULL UNIQUE,
+    title       text NOT NULL,
+    description text NOT NULL DEFAULT '',
+    icon        text NOT NULL,
+    sort        integer NOT NULL DEFAULT 0,
+    created_at  timestamptz NOT NULL DEFAULT now(),
+    updated_at  timestamptz NOT NULL DEFAULT now(),
+    CONSTRAINT categories_slug_format CHECK (slug ~ '^[a-z0-9]+(-[a-z0-9]+)*$'),
+    CONSTRAINT categories_title_not_empty CHECK (btrim(title) <> '')
+);
+
+COMMENT ON TABLE public.categories IS '链接分类表';
+COMMENT ON COLUMN public.categories.id IS '分类 ID，内部关联用';
+COMMENT ON COLUMN public.categories.slug IS '页面地址（路由）标识';
+COMMENT ON COLUMN public.categories.title IS '分类标题';
+COMMENT ON COLUMN public.categories.description IS '分类描述';
+COMMENT ON COLUMN public.categories.icon IS '分类图标标识';
+COMMENT ON COLUMN public.categories.sort IS '分类排序，越小越靠前';
+COMMENT ON COLUMN public.categories.created_at IS '创建时间';
+COMMENT ON COLUMN public.categories.updated_at IS '更新时间，触发器自动刷新';
+
+-- 链接表
+CREATE TABLE public.links (
+    id          bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
+    category_id bigint NOT NULL,
+    title       text NOT NULL,
+    description text NOT NULL DEFAULT '',
+    url         text NOT NULL,
+    icon        text,
+    keywords    text[] NOT NULL DEFAULT ARRAY[]::text[],
+    sort        integer NOT NULL DEFAULT 0,
+    pinned      boolean NOT NULL DEFAULT false,
+    pinned_sort integer,
+    created_at  timestamptz NOT NULL DEFAULT now(),
+    updated_at  timestamptz NOT NULL DEFAULT now(),
+    CONSTRAINT links_category_fk
+        FOREIGN KEY (category_id) REFERENCES public.categories (id)
+        ON DELETE RESTRICT,
+    CONSTRAINT links_title_not_empty CHECK (btrim(title) <> ''),
+    CONSTRAINT links_url_not_empty CHECK (btrim(url) <> ''),
+    CONSTRAINT links_pinned_sort_consistent CHECK (pinned = (pinned_sort IS NOT NULL)),
+    CONSTRAINT links_keywords_one_dimension
+        CHECK (cardinality(keywords) = 0 OR array_ndims(keywords) = 1),
+    CONSTRAINT links_keywords_no_null_elements
+        CHECK (array_position(keywords, NULL) IS NULL)
+);
+
+COMMENT ON TABLE public.links IS '链接表，归属分类';
+COMMENT ON COLUMN public.links.id IS '链接 ID';
+COMMENT ON COLUMN public.links.category_id IS '所属分类 ID，删分类前需先处理链接';
+COMMENT ON COLUMN public.links.title IS '链接标题';
+COMMENT ON COLUMN public.links.description IS '链接描述';
+COMMENT ON COLUMN public.links.url IS '链接地址，应用层校验，去尾斜杠后全局唯一';
+COMMENT ON COLUMN public.links.icon IS '链接图标，可空，前端回退';
+COMMENT ON COLUMN public.links.keywords IS '搜索关键词数组，供本地搜索匹配';
+COMMENT ON COLUMN public.links.sort IS '分类内排序，越小越靠前';
+COMMENT ON COLUMN public.links.pinned IS '首页快捷入口（手动固定），非点击排行';
+COMMENT ON COLUMN public.links.pinned_sort IS '首页快捷入口顺序，越小越靠前';
+COMMENT ON COLUMN public.links.created_at IS '创建时间';
+COMMENT ON COLUMN public.links.updated_at IS '更新时间，触发器自动刷新';
+
+-- 索引
+CREATE INDEX categories_order_idx
+    ON public.categories (sort, id);
+
+CREATE INDEX links_category_order_idx
+    ON public.links (category_id, sort, id);
+
+CREATE INDEX links_pinned_order_idx
+    ON public.links (pinned_sort, id)
+    WHERE pinned;
+
+CREATE UNIQUE INDEX links_normalized_url_unique
+    ON public.links (rtrim(url, '/'));
+
+-- 触发器
+CREATE TRIGGER users_set_updated_at
+    BEFORE UPDATE ON public.users
+    FOR EACH ROW
+    EXECUTE FUNCTION public.set_updated_at();
+
+CREATE TRIGGER categories_set_updated_at
+    BEFORE UPDATE ON public.categories
+    FOR EACH ROW
+    EXECUTE FUNCTION public.set_updated_at();
+
+CREATE TRIGGER links_set_updated_at
+    BEFORE UPDATE ON public.links
+    FOR EACH ROW
+    EXECUTE FUNCTION public.set_updated_at();
+
+COMMIT;