webui: switch to hash-based routing (alternative of #16079) (#16157)

* Switched web UI to hash-based routing

* Added hash to missed goto function call

* Removed outdated SPA handling code

* Fixed broken sidebar home link

tools/server/webui/src/lib/components/app/chat/ChatSidebar/ChatSidebar.svelte

@@ -64,13 +64,13 @@
 			searchQuery = '';
 		}
 
-		await goto(`/chat/${id}`);
+		await goto(`#/chat/${id}`);
 	}
 </script>
 
 <ScrollArea class="h-[100vh]">
 	<Sidebar.Header class=" top-0 z-10 gap-6 bg-sidebar/50 px-4 pt-4 pb-2 backdrop-blur-lg md:sticky">
-		<a href="/" onclick={handleMobileSidebarItemClick}>
+		<a href="#/" onclick={handleMobileSidebarItemClick}>
 			<h1 class="inline-flex items-center gap-1 px-2 text-xl font-semibold">llama.cpp</h1>
 		</a>
 

tools/server/webui/src/lib/components/app/chat/ChatSidebar/ChatSidebarActions.svelte

@@ -51,7 +51,7 @@
 	{:else}
 		<Button
 			class="w-full justify-between hover:[&>kbd]:opacity-100"
-			href="/?new_chat=true"
+			href="?new_chat=true#/"
 			onclick={handleMobileSidebarItemClick}
 			variant="ghost"
 		>

tools/server/webui/src/lib/components/app/server/ServerErrorSplash.svelte

@@ -64,7 +64,7 @@
 			updateConfig('apiKey', apiKeyInput.trim());
 
 			// Test the API key by making a real request to the server
-			const response = await fetch('/props', {
+			const response = await fetch('./props', {
 				headers: {
 					'Content-Type': 'application/json',
 					Authorization: `Bearer ${apiKeyInput.trim()}`
@@ -77,7 +77,7 @@
 
 				// Show success state briefly, then navigate to home
 				setTimeout(() => {
-					goto('/');
+					goto(`#/`);
 				}, 1000);
 			} else {
 				// API key is invalid - User Story A