fix: use format string for datastar.PostSSE in chat component

PostSSE requires a constant format string; pass "%s" with the URL
as an argument instead of passing the URL directly.

chat/components/chat.templ

@@ -43,7 +43,7 @@ templ Chat(messages []chat.Message, cfg Config) {
 					autocomplete="off"
 					data-bind="chatMsg"
 					data-on:keydown.stop=""
-					data-on:keydown.key_enter={ datastar.PostSSE(cfg.PostURL) }
+				data-on:keydown.key_enter={ datastar.PostSSE("%s", cfg.PostURL) }
 			/>
 		} else {
 			<input
@@ -51,12 +51,12 @@ templ Chat(messages []chat.Message, cfg Config) {
 				placeholder="Chat..."
 				autocomplete="off"
 				data-bind="chatMsg"
-					data-on:keydown.enter={ datastar.PostSSE(cfg.PostURL) }
+				data-on:keydown.enter={ datastar.PostSSE("%s", cfg.PostURL) }
 			/>
 		}
 		<button
 			type="button"
-				data-on:click={ datastar.PostSSE(cfg.PostURL) }
+			data-on:click={ datastar.PostSSE("%s", cfg.PostURL) }
 			>
 				Send
 			</button>