feat(chat): sync multi-role backend APIs

src/app/chat/components/__tests__/chat-area-scroll.test.tsx

@@ -235,7 +235,7 @@ function renderChatArea(
   act(() => {
     root.render(
       <ChatArea
-        characterId="character_elio"
+        characterId="elio"
         messages={messages}
         isReplyingAI={false}
         initialScrollReady={initialScrollReady}

src/app/chat/components/__tests__/tailwind-components.test.tsx

@@ -127,7 +127,7 @@ describe("chat Tailwind components", () => {
   it("renders ImageBubble openable and paywalled states", () => {
     const openableHtml = renderToStaticMarkup(
       <ImageBubble
-        characterId="character_elio"
+        characterId="elio"
         messageId="message-1"
         imageUrl="/chat-image.png"
         onOpenImage={() => undefined}
@@ -135,7 +135,7 @@ describe("chat Tailwind components", () => {
     );
     const paywalledHtml = renderToStaticMarkup(
       <ImageBubble
-        characterId="character_elio"
+        characterId="elio"
         imageUrl="/locked-image.png"
         imagePaywalled
       />,

src/app/chat/components/chat-input-text-field.tsx

@@ -73,6 +73,7 @@ export const ChatInputTextField = forwardRef<
         onBlur={() => onFocusChange?.(false)}
         placeholder={placeholder}
         disabled={disabled}
+        maxLength={4000}
         autoFocus={autoFocus}
         rows={1}
         aria-label="Message"