feat: image rendering, sidebar toggle, contribute section; fix: private repo update check; bump v0.2.1

src/style/chat.css

@@ -22,12 +22,21 @@
 
 /* 会话侧边栏 */
 .chat-sidebar {
-  width: 220px;
-  border-right: 1px solid var(--border);
+  width: 0;
+  min-width: 0;
+  border-right: none;
   background: var(--bg-primary);
   display: flex;
   flex-direction: column;
   flex-shrink: 0;
+  overflow: hidden;
+  transition: width 0.2s ease, min-width 0.2s ease, border-right 0.2s ease;
+}
+
+.chat-sidebar.open {
+  width: 220px;
+  min-width: 220px;
+  border-right: 1px solid var(--border);
 }
 
 .chat-sidebar-header {
@@ -413,6 +422,56 @@
   flex-shrink: 0;
 }
 
+/* 连接引导遮罩 */
+.chat-connect-overlay {
+  position: absolute;
+  inset: 0;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  background: var(--bg-primary, #fff);
+  z-index: 20;
+}
+
+.chat-connect-card {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  gap: 16px;
+  max-width: 360px;
+  padding: 40px 32px;
+  text-align: center;
+}
+
+.chat-connect-icon {
+  color: var(--text-tertiary);
+  opacity: 0.6;
+}
+
+.chat-connect-title {
+  font-size: var(--font-size-lg, 18px);
+  font-weight: 600;
+  color: var(--text-primary);
+}
+
+.chat-connect-desc {
+  font-size: var(--font-size-sm, 13px);
+  color: var(--text-secondary);
+  line-height: 1.5;
+}
+
+.chat-connect-actions {
+  display: flex;
+  gap: 8px;
+  margin-top: 4px;
+}
+
+.chat-connect-hint {
+  font-size: var(--font-size-xs, 11px);
+  color: var(--text-tertiary);
+  margin-top: 8px;
+}
+
 /* 会话列表 */
 .chat-session-list {
   flex: 1;
@@ -611,3 +670,28 @@
 .chat-attachment-del:hover {
   background: rgba(255,0,0,0.8);
 }
+
+/* 图片灯箱 */
+.chat-lightbox {
+  position: fixed;
+  top: 0;
+  left: 0;
+  width: 100%;
+  height: 100%;
+  background: rgba(0, 0, 0, 0.85);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  z-index: 9999;
+  cursor: pointer;
+  backdrop-filter: blur(4px);
+}
+
+.chat-lightbox-img {
+  max-width: 90%;
+  max-height: 90%;
+  border-radius: 8px;
+  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.5);
+  cursor: default;
+  object-fit: contain;
+}