feat: add feature flag to control diff sidebar visibility

Introduce NEXT_PUBLIC_ENABLE_DIFF_SIDEBAR environment variable to
enable/disable the diff sidebar button and keyboard shortcut globally.

Author: ulrikandersen

.env.example

@@ -24,3 +24,4 @@ GITHUB_APP_ID=123456
 GITHUB_PRIVATE_KEY_BASE_64=base 64 encoded version of the private key - see README.md for more info
 ENCRYPTION_PUBLIC_KEY_BASE_64=base 64 encoded version of the public key
 ENCRYPTION_PRIVATE_KEY_BASE_64=base 64 encoded version of the private key
+NEXT_PUBLIC_ENABLE_DIFF_SIDEBAR=true

src/features/sidebar/view/SecondarySplitHeader.tsx

@@ -11,6 +11,8 @@ import useDiffbarOpen from "@/features/sidebar/data/useDiffbarOpen"
 import ToggleMobileToolbarButton from "./internal/secondary/ToggleMobileToolbarButton"
 import { useProjectSelection } from "@/features/projects/data"
 
+const isDiffFeatureEnabled = process.env.NEXT_PUBLIC_ENABLE_DIFF_SIDEBAR === "true"
+
 const SecondarySplitHeader = ({
   mobileToolbar,
   children
@@ -48,11 +50,13 @@ const SecondarySplitHeader = ({
             )}
           </Stack>
         </Box>
-        <ToggleDiffButton
-          isDiffbarOpen={isDiffbarOpen}
-          onClick={setDiffbarOpen}
-          isDiffAvailable={!!specification?.diffURL}
-        />
+        {isDiffFeatureEnabled && (
+          <ToggleDiffButton
+            isDiffbarOpen={isDiffbarOpen}
+            onClick={setDiffbarOpen}
+            isDiffAvailable={!!specification?.diffURL}
+          />
+        )}
       </Box>
       {mobileToolbar && (
         <Collapse in={isMobileToolbarVisible}>

src/features/sidebar/view/internal/ClientSplitView.tsx

@@ -10,6 +10,8 @@ import PrimaryContainer from "./primary/Container"
 import SecondaryContainer from "./secondary/Container"
 import RightContainer from "./tertiary/RightContainer"
 
+const isDiffFeatureEnabled = process.env.NEXT_PUBLIC_ENABLE_DIFF_SIDEBAR === "true"
+
 const ClientSplitView = ({
   sidebar,
   children,
@@ -51,7 +53,7 @@ const ClientSplitView = ({
 
   useKeyboardShortcut(event => {
     const isActionKey = isMac() ? event.metaKey : event.ctrlKey
-    if (isActionKey && event.key === "k") {
+    if (isDiffFeatureEnabled && isActionKey && event.key === "k") {
       event.preventDefault()
       setRightSidebarOpen(!isRightSidebarOpen)
     }