fix(dictation): drop the under-input interim preview in chat

The live partial transcript was shown as a dimmed line under the chat textarea,
but each segment only flickers there for an instant before its final lands in
the draft — the preview was unreadable noise. Remove it: realtime partials are
no longer rendered separately; finalized segments are appended straight into the
draft (where the user actually reads them). Editor dictation (inline ghost at the
caret) is unaffected.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

apps/client/src/features/ai-chat/components/chat-input.tsx

@@ -1,9 +1,8 @@
-import { KeyboardEvent, useState } from "react";
+import { KeyboardEvent } from "react";
 import {
   ActionIcon,
   Group,
   Stack,
-  Text,
   Textarea,
   Tooltip,
 } from "@mantine/core";
@@ -48,16 +47,12 @@ export default function ChatInput({
   const workspace = useAtomValue(workspaceAtom);
   const isDictationEnabled = workspace?.settings?.ai?.dictation === true;
   const isRealtime = workspace?.settings?.ai?.dictationRealtime === true;
-  // Live interim (partial) transcript shown as a dimmed tail under the input.
-  const [interim, setInterim] = useState("");
 
   const send = (): void => {
     const text = value.trim();
     if (!text || isStreaming || disabled) return;
     onSend(text);
     setValue("");
-    // Drop any leftover partial when a message is sent.
-    setInterim("");
   };
 
   const handleKeyDown = (e: KeyboardEvent<HTMLTextAreaElement>): void => {
@@ -90,11 +85,11 @@ export default function ChatInput({
           <RealtimeMicButton
             size="lg"
             disabled={isStreaming || disabled}
-            onInterim={(text) => setInterim(text)}
-            onFinal={(text) => {
-              setValue((v) => appendFinalToDraft(v, text));
-              setInterim("");
-            }}
+            // No separate interim preview in the chat: partials are not shown
+            // under the input (they only flicker before the final lands in the
+            // draft). Each finalized segment is appended straight into the draft.
+            onInterim={() => {}}
+            onFinal={(text) => setValue((v) => appendFinalToDraft(v, text))}
           />
         ) : (
           <MicButton
@@ -129,11 +124,6 @@ export default function ChatInput({
         </Tooltip>
       )}
       </Group>
-      {interim && (
-        <Text size="sm" c="dimmed">
-          {interim}
-        </Text>
-      )}
     </Stack>
   );
 }