feat: 添加用户注册登录功能，实现数据和配置的用户隔离

- 新增 users 和 user_settings 表，repositories/analyses/review_notes 添加 user_id 列
- 实现基于邮箱+密码的注册登录，密码使用 bcrypt 哈希
- 使用 gin-contrib/sessions cookie-based session 管理
- 所有仓库、分析记录、review notes 按用户隔离
- 用户设置（LLM 配置、review 参数、缓存配置）独立存储
- 新增登录/注册页面，导航栏显示用户邮箱和退出按钮
- 前端 fetch 请求统一添加 credentials: 'same-origin'
- 支持 SESSION_SECRET 环境变量配置会话密钥

templates/pages/review.html

@@ -129,14 +129,14 @@
         // Load refs on page load
         async function loadRefs() {
             try {
-                const resp = await fetch(`/api/repos/${repoId}/refs`);
+                const resp = await fetch(`/api/repos/${repoId}/refs`, { credentials: 'same-origin' });
                 if (!resp.ok) throw new Error('Failed to load refs');
                 const refs = await resp.json();
 
                 // Fetch recent commits for the "Recent Commits" group
                 let commits = [];
                 try {
-                    const graphResp = await fetch(`/api/repos/${repoId}/graph?max_commits=20`);
+                    const graphResp = await fetch(`/api/repos/${repoId}/graph?max_commits=20`, { credentials: 'same-origin' });
                     if (graphResp.ok) {
                         const gd = await graphResp.json();
                         commits = gd.commits || [];
@@ -437,7 +437,7 @@
 
         async function loadHistoryList() {
             try {
-                const resp = await fetch(`/api/repos/${repoId}/review/analyses`);
+                const resp = await fetch(`/api/repos/${repoId}/review/analyses`, { credentials: 'same-origin' });
                 if (!resp.ok) return;
                 const analyses = await resp.json();
 
@@ -465,7 +465,7 @@
 
             try {
                 // Fetch the review result
-                const resp = await fetch(`/api/repos/${repoId}/review/analyses/${analysisId}`);
+                const resp = await fetch(`/api/repos/${repoId}/review/analyses/${analysisId}`, { credentials: 'same-origin' });
                 if (!resp.ok) throw new Error('Failed to load review');
                 const data = await resp.json();
 
@@ -518,7 +518,7 @@
                 const head = data.head_ref;
 
                 // Load diff from API
-                const diffResp = await fetch(`/api/repos/${repoId}/diff?base=${encodeURIComponent(base)}&head=${encodeURIComponent(head)}`);
+                const diffResp = await fetch(`/api/repos/${repoId}/diff?base=${encodeURIComponent(base)}&head=${encodeURIComponent(head)}`, { credentials: 'same-origin' });
                 if (diffResp.ok) {
                     const diffData = await diffResp.json();
                     const diffString = diffData.diff || '';