Use official logo in Goose web (#3012)

Co-authored-by: Sam Bradbury <Sam Bradbury>

crates/goose-cli/static/style.css

@@ -50,6 +50,10 @@
         --tool-bg: #f8f9fa;
         --code-bg: #f5f5f5;
     }
+
+    header h1::before {
+        background-image: url('/static/img/logo_light.png');
+    }
 }
 
 * {
@@ -94,8 +98,14 @@ header h1 {
 }
 
 header h1::before {
-    content: "🪿";
-    font-size: 1.5rem;
+    content: "";
+    width: 32px;
+    height: 32px;
+    background-image: url('/static/img/logo_dark.png');
+    background-size: contain;
+    background-repeat: no-repeat;
+    background-position: center;
+    display: inline-block;
 }
 
 .status {
@@ -460,20 +470,20 @@ header h1::before {
         padding: 1rem;
         gap: 1rem;
     }
-    
+
     .message {
         max-width: 90%;
         padding: 0.875rem 1rem;
     }
-    
+
     .input-container {
         padding: 1rem;
     }
-    
+
     header {
         padding: 0.75rem 1rem;
     }
-    
+
     .welcome-message {
         padding: 2rem 1rem;
     }