enh: mermaid copy content button

src/lib/components/chat/Artifacts.svelte

@@ -191,7 +191,7 @@
 					showArtifacts.set(false);
 				}}
 			>
-				<ArrowLeft className="size-3.5" />
+				<ArrowLeft className="size-3.5  text-gray-900 dark:text-white" />
 			</button>
 		</div>
 

src/lib/components/chat/Messages/CodeBlock.svelte

@@ -302,6 +302,7 @@ __builtins__.input = input`);
 				<SvgPanZoom
 					className=" border border-gray-50 dark:border-gray-850 rounded-lg max-h-fit overflow-hidden"
 					svg={mermaidHtml}
+					content={_token.text}
 				/>
 			{:else}
 				<pre class="mermaid">{code}</pre>