feat: Round 5 - Memory Service, Tool Engine, Call Records, Thinking Logs

- Fix: Session history flash (race condition + WS guard)
- Fix: Chat background overlay + sidebar transparency
- Fix: IoT device control (Chinese action names, status field)
- Feat: Independent memory-service (port 8091, 13 endpoints)
- Feat: Independent tool-engine service (port 8092, 13 tools)
- Feat: Tool call logs with paginated DevTools panel
- Feat: Thinking log records with DevTools panel
- Feat: Future development roadmap document
- Chore: Updated .gitignore, go.work, DevTools config
- Chore: 5-service health check, project review docs

frontend/web/src/index.css

@@ -105,12 +105,24 @@
 
 /* ===== 聊天背景 ===== */
 .chat-background {
+  position: relative;
+  isolation: isolate;
   background-image: url('/images/Cyrene_ChatBackground/Vertical/2nd_Form/1.png');
   background-size: cover;
   background-position: center;
   background-attachment: fixed;
 }
 
+/* 半透明遮罩：避免背景色彩过于鲜艳影响阅读 */
+.chat-background::before {
+  content: '';
+  position: absolute;
+  inset: 0;
+  background: rgba(255, 255, 255, 0.5);
+  pointer-events: none;
+  z-index: -1;
+}
+
 /* 横屏时使用 Landscape 背景 */
 @media (orientation: landscape) {
   .chat-background {
@@ -128,4 +140,8 @@
     background: rgba(244, 114, 182, 0.2);
     color: #fbcfe8;
   }
+
+  .chat-background::before {
+    background: rgba(0, 0, 0, 0.4);
+  }
 }