enh: valve field desc support

src/lib/components/chat/Settings/Valves.svelte

@@ -203,7 +203,7 @@
 								</div>
 
 								{#if (valves[property] ?? null) !== null}
-									<div class="flex mt-0.5 space-x-2">
+									<div class="flex mt-0.5 mb-1 space-x-2">
 										<div class=" flex-1">
 											<input
 												class="w-full rounded-lg py-2 px-4 text-sm dark:text-gray-300 dark:bg-gray-850 outline-none"
@@ -216,6 +216,12 @@
 										</div>
 									</div>
 								{/if}
+
+								{#if (valvesSpec.properties[property]?.description ?? null) !== null}
+									<div class="text-xs text-gray-500">
+										{valvesSpec.properties[property].description}
+									</div>
+								{/if}
 							</div>
 						{/each}
 					{:else}