fix(lint): clear the 7 exhaustive-deps warnings carried all session

Every lint run this session reported the same 7 warnings across 4 files.
Fixed properly, not suppressed:

- Chat/index.tsx: effect depended on the whole liveChatStatus object;
  narrowed to liveChatStatus?.requestId, the one field it actually reads.
- Heartbeat/index.tsx: fetchConfig wrapped in useCallback([form, t]) and
  added to its effect's dependency array, instead of an empty array
  silencing the warning on a function that closes over both.
- Environments/index.tsx: `t` (i18n) added to 4 useCallback dependency
  arrays that read it but didn't declare it.
- ModelsSection.tsx: effect depended on the currentSlot object reference;
  extracted currentProviderId/currentModel primitives so it only reruns
  when the actual values change, not on every new object identity.

Build 0 errors, lint 0 errors / 0 warnings (was 7).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/pages/Chat/index.tsx

@@ -922,7 +922,7 @@ export default function ChatPage() {
   }, [activeTab]);
 
   useEffect(() => {
-    if (liveChatStatus) {
+    if (liveChatStatus?.requestId) {
       forceFollowUntilRef.current = Date.now() + 15_000;
       scrollChatToBottom(chatStageRef.current);
       return;

src/pages/Control/Heartbeat/index.tsx

@@ -1,4 +1,4 @@
-import { useEffect, useState } from "react";
+import { useCallback, useEffect, useState } from "react";
 import {
   Button,
   Card,
@@ -72,7 +72,7 @@ function HeartbeatPage() {
   const [saving, setSaving] = useState(false);
   const [form] = Form.useForm<HeartbeatFormValues>();
 
-  const fetchConfig = async () => {
+  const fetchConfig = useCallback(async () => {
     setLoading(true);
     try {
       const data = await api.getHeartbeatConfig();
@@ -92,11 +92,11 @@ function HeartbeatPage() {
     } finally {
       setLoading(false);
     }
-  };
+  }, [form, t]);
 
   useEffect(() => {
     fetchConfig();
-  }, []);
+  }, [fetchConfig]);
 
   const onFinish = async (values: HeartbeatFormValues) => {
     const every =

src/pages/Settings/Environments/index.tsx

@@ -178,7 +178,7 @@ function EnvironmentsPage() {
         onOk: doRemove,
       });
     },
-    [workingRows, ensureLocal, envVars.length],
+    [workingRows, ensureLocal, envVars.length, t],
   );
 
   const removeSelected = useCallback(() => {
@@ -211,7 +211,7 @@ function EnvironmentsPage() {
       cancelText: t("common.cancel"),
       onOk: doRemove,
     });
-  }, [selected, workingRows, ensureLocal, envVars.length]);
+  }, [selected, workingRows, ensureLocal, envVars.length, t]);
 
   /* ---- validate & save ---- */
 
@@ -231,7 +231,7 @@ function EnvironmentsPage() {
     }
     setKeyErrors(errors);
     return Object.keys(errors).length === 0;
-  }, [workingRows]);
+  }, [workingRows, t]);
 
   const handleSave = useCallback(async () => {
     if (!validate()) return;
@@ -254,7 +254,7 @@ function EnvironmentsPage() {
     } finally {
       setSaving(false);
     }
-  }, [validate, workingRows, fetchAll]);
+  }, [validate, workingRows, fetchAll, t]);
 
   const handleReset = useCallback(() => {
     setRows(null);

src/pages/Settings/Models/components/sections/ModelsSection.tsx

@@ -44,6 +44,8 @@ export function ModelsSection({
   );
 
   const currentSlot = activeModels?.active_llm;
+  const currentProviderId = currentSlot?.provider_id;
+  const currentModel = currentSlot?.model;
 
   const eligible = useMemo(
     () =>
@@ -70,12 +72,12 @@ export function ModelsSection({
   );
 
   useEffect(() => {
-    if (currentSlot) {
-      setSelectedProviderId(currentSlot.provider_id || undefined);
-      setSelectedModel(currentSlot.model || undefined);
+    if (currentProviderId || currentModel) {
+      setSelectedProviderId(currentProviderId || undefined);
+      setSelectedModel(currentModel || undefined);
     }
     setDirty(false);
-  }, [currentSlot?.provider_id, currentSlot?.model]);
+  }, [currentProviderId, currentModel]);
 
   const chosenProvider = providers.find((p) => p.id === selectedProviderId);
   const modelOptions = chosenProvider?.models ?? [];