feat: 优化 Windows 缓存加载和图片显示

src/renderer/src/assets/main.css

@@ -244,6 +244,18 @@ body {
   margin-bottom: 14px;
 }
 
+.message-loading-pill {
+  align-self: center;
+  margin: 0 0 12px;
+  padding: 5px 12px;
+  border-radius: 999px;
+  background: rgba(255, 255, 255, 0.78);
+  color: #7a858b;
+  font-size: 12px;
+  line-height: 1.4;
+  box-shadow: 0 1px 4px rgba(15, 23, 42, 0.08);
+}
+
 .wechat-message-row {
   display: flex;
   align-items: flex-start;
@@ -947,11 +959,12 @@ body {
   justify-content: center;
   background: rgba(16, 24, 28, 0.28);
   backdrop-filter: blur(1px);
+  overscroll-behavior: contain;
 }
 
 .image-viewer-window {
-  width: min(900px, 86vw);
-  height: min(700px, 82vh);
+  width: min(1280px, 96vw);
+  height: min(900px, 92vh);
   display: flex;
   flex-direction: column;
   overflow: hidden;
@@ -1018,14 +1031,17 @@ body {
   align-items: center;
   justify-content: center;
   padding: 28px;
-  overflow: auto;
+  overflow: hidden;
+  overscroll-behavior: contain;
   cursor: grab;
   user-select: none;
 }
 
 .image-viewer-stage img {
-  max-width: 100%;
-  max-height: 100%;
+  max-width: none;
+  max-height: none;
+  width: auto;
+  height: auto;
   object-fit: contain;
   box-shadow: 0 3px 16px rgba(0, 0, 0, 0.12);
   transform-origin: center center;
@@ -1329,6 +1345,28 @@ body {
   color: #6f767c;
 }
 
+.boot-splash-detail {
+  min-height: 18px;
+  font-size: 12px;
+  color: #8a9298;
+}
+
+.boot-splash-progress {
+  width: min(320px, 72vw);
+  height: 6px;
+  margin-top: 2px;
+  overflow: hidden;
+  border-radius: 999px;
+  background: rgba(7, 193, 96, 0.12);
+}
+
+.boot-splash-progress-bar {
+  height: 100%;
+  border-radius: inherit;
+  background: #07c160;
+  transition: width 0.18s ease-out;
+}
+
 /* 设置面板 */
 .settings-overlay {
   position: fixed;