feat: implement file upload functionality and create file serving endpoint

src/routes/(admin)/admin/characters/+page.svelte

@@ -30,6 +30,14 @@
 		}, 3000);
 	};
 
+	const handleFileSelect = (event: Event) => {
+		const target = event.target as HTMLInputElement;
+		if (target.files && target.files.length > 0) {
+			// Clear pictureUrl when a file is selected
+			editForm.pictureUrl = '';
+		}
+	};
+
 	const getFandomUrl = (url: string | null | undefined) => {
 		if (!url) return null;
 		if (url.startsWith('http://') || url.startsWith('https://')) return url;
@@ -516,6 +524,7 @@
 					class="mt-6 space-y-4"
 					method="POST"
 					action="?/update"
+					enctype="multipart/form-data"
 					use:enhance={() => {
 						isSaving = true;
 						return async ({ result }) => {
@@ -776,10 +785,24 @@
 								name="pictureUrl"
 								bind:value={editForm.pictureUrl}
 								placeholder={selectedChar?.pictureUrl || ''}
-							class="w-full rounded-lg border border-gray-500 bg-slate-800 px-3 py-2 text-white placeholder:text-gray-400/40"
+								class="w-full rounded-lg border border-gray-500 bg-slate-800 px-3 py-2 text-white placeholder:text-gray-400/40"
 							/>
 						</div>
 
+						<div>
+							<label for="char-picture-file" class="block text-sm font-medium text-gray-300 mb-2">Or Upload Picture</label>
+							<input
+								type="file"
+								id="char-picture-file"
+								name="pictureFile"
+								accept="image/*"
+								onchange={handleFileSelect}
+								class="w-full rounded-lg border border-gray-500 bg-slate-800 px-3 py-2 text-white file:mr-4 file:py-2 file:px-4 file:rounded file:border-0 file:text-sm file:font-semibold file:bg-amber-600 file:text-white hover:file:bg-amber-700"
+							/>
+							<p class="mt-1 text-xs text-gray-400">File will be saved as {selectedChar?.id}.jpg/png/etc</p>
+						</div>
+
+
 						<div>
 							<label for="char-url" class="block text-sm font-medium text-gray-300 mb-2">Fandom URL</label>
 							<input