feat: 省略旧消息的代码 diff 展示，仅保留最新消息的完整 diff

src/components/Message.tsx

@@ -77,6 +77,8 @@ export type Props = {
   lastThinkingBlockId?: string | null
   /** UUID of the latest user bash output message (for auto-expanding) */
   latestBashOutputUUID?: string | null
+  /** Whether to collapse diff display for this message */
+  shouldCollapseDiffs?: boolean
 }
 
 function MessageImpl({
@@ -99,6 +101,7 @@ function MessageImpl({
   isUserContinuation = false,
   lastThinkingBlockId,
   latestBashOutputUUID,
+  shouldCollapseDiffs,
 }: Props): React.ReactNode {
   switch (message.type) {
     case 'attachment':
@@ -181,6 +184,7 @@ function MessageImpl({
               isUserContinuation={isUserContinuation}
               lookups={lookups}
               isTranscriptMode={isTranscriptMode}
+              shouldCollapseDiffs={shouldCollapseDiffs}
             />
           ))}
         </Box>
@@ -293,6 +297,7 @@ function UserMessage({
   isUserContinuation,
   lookups,
   isTranscriptMode,
+  shouldCollapseDiffs,
 }: {
   message: NormalizedUserMessage
   addMargin: boolean
@@ -309,6 +314,7 @@ function UserMessage({
   isUserContinuation: boolean
   lookups: ReturnType<typeof buildMessageLookups>
   isTranscriptMode: boolean
+  shouldCollapseDiffs?: boolean
 }): React.ReactNode {
   const { columns } = useTerminalSize()
   switch (param.type) {
@@ -344,6 +350,7 @@ function UserMessage({
           verbose={verbose}
           width={columns - 5}
           isTranscriptMode={isTranscriptMode}
+          shouldCollapseDiffs={shouldCollapseDiffs}
         />
       )
     default:

src/components/MessageRow.tsx

@@ -55,6 +55,7 @@ export type Props = {
   columns: number
   isLoading: boolean
   lookups: ReturnType<typeof buildMessageLookups>
+  shouldCollapseDiffs?: boolean
 }
 
 /**
@@ -141,6 +142,7 @@ function MessageRowImpl({
   columns,
   isLoading,
   lookups,
+  shouldCollapseDiffs,
 }: Props): React.ReactNode {
   const isTranscriptMode = screen === 'transcript'
   const isGrouped = msg.type === 'grouped_tool_use'
@@ -221,6 +223,7 @@ function MessageRowImpl({
       isUserContinuation={isUserContinuation}
       lastThinkingBlockId={lastThinkingBlockId}
       latestBashOutputUUID={latestBashOutputUUID}
+      shouldCollapseDiffs={shouldCollapseDiffs}
     />
   )
   // OffscreenFreeze: the outer React.memo already bails for static messages,

src/components/Messages.tsx

@@ -814,6 +814,12 @@ const MessagesImpl = ({
           streamingToolUseIDs,
         ))
 
+    // Collapse diffs for messages beyond the latest N messages.
+    // verbose (ctrl+o) overrides and always shows full diffs.
+    const DIFF_COLLAPSE_DISTANCE = 0
+    const shouldCollapseDiffs =
+      renderableMessages.length - 1 - index > DIFF_COLLAPSE_DISTANCE
+
     const k = messageKey(msg)
     const row = (
       <MessageRow
@@ -838,6 +844,7 @@ const MessagesImpl = ({
         columns={columns}
         isLoading={isLoading}
         lookups={lookups}
+        shouldCollapseDiffs={shouldCollapseDiffs}
       />
     )
 

src/components/messages/UserToolResultMessage/UserToolResultMessage.tsx

@@ -27,6 +27,7 @@ type Props = {
   verbose: boolean
   width: number | string
   isTranscriptMode?: boolean
+  shouldCollapseDiffs?: boolean
 }
 
 export function UserToolResultMessage({
@@ -39,6 +40,7 @@ export function UserToolResultMessage({
   verbose,
   width,
   isTranscriptMode,
+  shouldCollapseDiffs,
 }: Props): React.ReactNode {
   const toolUse = useGetToolFromMessages(param.tool_use_id, tools, lookups)
   if (!toolUse) {
@@ -96,6 +98,7 @@ export function UserToolResultMessage({
       verbose={verbose}
       width={width}
       isTranscriptMode={isTranscriptMode}
+      shouldCollapseDiffs={shouldCollapseDiffs}
     />
   )
 }

src/components/messages/UserToolResultMessage/UserToolSuccessMessage.tsx

@@ -33,6 +33,7 @@ type Props = {
   verbose: boolean
   width: number | string
   isTranscriptMode?: boolean
+  shouldCollapseDiffs?: boolean
 }
 
 export function UserToolSuccessMessage({
@@ -46,6 +47,7 @@ export function UserToolSuccessMessage({
   verbose,
   width,
   isTranscriptMode,
+  shouldCollapseDiffs,
 }: Props): React.ReactNode {
   const [theme] = useTheme()
   // Hook stays inside feature() ternary so external builds don't pay a
@@ -83,12 +85,16 @@ export function UserToolSuccessMessage({
   }
   const toolResult = parsedOutput?.data ?? message.toolUseResult
 
+  // Collapse diff display for old messages (verbose/ctrl+o overrides)
+  const effectiveStyle =
+    shouldCollapseDiffs && !verbose ? 'condensed' : style
+
   const renderedMessage =
     tool.renderToolResultMessage?.(
       toolResult as never,
       filterToolProgressMessages(progressMessagesForMessage),
       {
-        style,
+        style: effectiveStyle,
         theme,
         tools,
         verbose,