Implement knowledge base page routing and enhance ComponentsKnowledgePage

- Update the main knowledge page to support a list mode.
- Add new pages for creating and editing knowledge bases, utilizing the ComponentsKnowledgePage component with appropriate modes.
- Introduce a new API method for retrieving knowledge base details by ID.
- Enhance the ComponentsKnowledgePage to handle different modes (list, create, edit) and improve user interaction with knowledge bases.

frontend/src/app/components/knowledge/[id]/page.tsx

@@ -0,0 +1,10 @@
+import { ComponentsKnowledgePage } from "@/components/pages/ComponentsKnowledgePage";
+
+export default async function Page({
+  params,
+}: {
+  params: Promise<{ id: string }>;
+}) {
+  const { id } = await params;
+  return <ComponentsKnowledgePage mode="edit" knowledgeBaseId={id} />;
+}

frontend/src/app/components/knowledge/new/page.tsx

@@ -0,0 +1,5 @@
+import { ComponentsKnowledgePage } from "@/components/pages/ComponentsKnowledgePage";
+
+export default function Page() {
+  return <ComponentsKnowledgePage mode="create" />;
+}

frontend/src/app/components/knowledge/page.tsx

@@ -1,5 +1,5 @@
 import { ComponentsKnowledgePage } from "@/components/pages/ComponentsKnowledgePage";
 
 export default function Page() {
-  return <ComponentsKnowledgePage />;
+  return <ComponentsKnowledgePage mode="list" />;
 }

frontend/src/components/pages/AssistantPage.tsx

@@ -3041,7 +3041,9 @@ function TextAreaField({
         placeholder={placeholder}
         onChange={(event) => onChange(event.target.value)}
         rows={rows}
-        className="resize-none border-hairline-strong bg-background text-foreground placeholder:text-muted-soft"
+        // Override ui/textarea's field-sizing-content so `rows` sets a real height
+        // instead of collapsing to min-h-16 when the value is short.
+        className="field-sizing-fixed min-h-32 resize-y border-hairline-strong bg-background text-foreground placeholder:text-muted-soft"
       />
     </label>
   );

frontend/src/lib/api.ts

@@ -377,6 +377,7 @@ export type KnowledgeBaseUpsert = Pick<
 
 export const knowledgeBasesApi = {
   list: () => request<KnowledgeBase[]>("/api/knowledge-bases"),
+  get: (id: string) => request<KnowledgeBase>(`/api/knowledge-bases/${id}`),
   create: (body: KnowledgeBaseUpsert) =>
     request<KnowledgeBase>("/api/knowledge-bases", { method: "POST", body: JSON.stringify(body) }),
   update: (id: string, body: KnowledgeBaseUpsert) =>