feat: parse and display rate_limit_event messages from Claude CLI

Closes #155

- Add RateLimitInfo struct and RateLimitEvent variant to ClaudeMessage
- Emit rate-limit OutputEvent with human-readable message in wsl_bridge
- Add rate-limit line type to TerminalLine union and Terminal rendering
- Display rate-limit lines in amber with [rate-limit] prefix
- Add Terminal.test.ts with 28 tests for getLineClass, getLinePrefix,
  formatTime, isToolContentLong, and truncateToolContent

src/lib/components/Terminal.svelte

@@ -93,6 +93,8 @@
         return "terminal-error";
       case "thinking":
         return "terminal-thinking";
+      case "rate-limit":
+        return "terminal-rate-limit";
       default:
         return "terminal-default";
     }
@@ -110,6 +112,8 @@
         return "[tool]";
       case "error":
         return "[error]";
+      case "rate-limit":
+        return "[rate-limit]";
       default:
         return "";
     }
@@ -362,6 +366,10 @@
     color: var(--terminal-error, #f87171);
   }
 
+  .terminal-rate-limit {
+    color: var(--terminal-rate-limit, #fb923c);
+  }
+
   .terminal-default {
     color: var(--text-primary);
   }