fix(app): suppress per-message Changed files section

packages/app/src/pages/session/timeline/rows-current.test.ts

@@ -308,6 +308,58 @@ describe("current session timeline rows", () => {
     }
   })
 
+  test("suppresses per-message DiffSummary rows even when summary.diffs is populated (#733)", () => {
+    const source = [
+      {
+        id: "msg_u",
+        type: "user",
+        text: "edit some files",
+        time: { created: 1 },
+        summary: {
+          additions: 10,
+          deletions: 3,
+          files: 2,
+          diffs: [
+            { file: "src/foo.ts", additions: 7, deletions: 2 },
+            { file: "src/bar.ts", additions: 3, deletions: 1 },
+          ],
+        },
+      },
+      {
+        id: "msg_a",
+        type: "assistant",
+        agent: "build",
+        model: { id: "model", providerID: "provider" },
+        content: [{ type: "text", text: "done" }],
+        time: { created: 2, completed: 3 },
+      },
+    ] as SessionMessageInfo[]
+    const normalized = normalizeSessionMessages("ses_1", source)
+    const messages = new Map(normalized.messages.map((message) => [message.id, message]))
+    // Inject summary.diffs onto the user message (normalizeSessionMessages
+    // strips it, but the live store propagates it)
+    const userMsg = messages.get("msg_u")!
+    ;(userMsg as any).summary = (source[0] as any).summary
+
+    const result = Timeline.constructSessionMessageRows(
+      source,
+      (messageID) => messages.get(messageID),
+      (messageID) => normalized.parts.get(messageID) ?? [],
+      true,
+      "idle",
+      true,
+      normalized.messages.filter((m) => m.role === "user"),
+    )
+
+    // No DiffSummary row should appear — the section is suppressed (#733)
+    const tags = result.rows.map((r) => r._tag)
+    expect(tags).not.toContain("DiffSummary")
+    // The normal rows are still present
+    expect(tags).toContain("UserMessage")
+    expect(tags).toContain("AssistantPart")
+    expect(tags).toContain("ThinkingMeta")
+  })
+
   test("turnStartedAt is threaded through Thinking and AssistantPart rows from user message time.created", () => {
     const source = [
       { id: "msg_u", type: "user", text: "go", time: { created: 1000 } },

packages/app/src/pages/session/timeline/rows.ts

@@ -3,7 +3,7 @@ import type { SessionMessageInfo } from "@opencode-ai/client/promise"
 import { AssistantMessage, Part, SessionStatus, UserMessage } from "@opencode-ai/sdk/v2"
 import { groupParts, renderable, type PartGroup } from "@opencode-ai/session-ui/message-part"
 import { TimelineRow, type SummaryDiff } from "./timeline-row"
-import { uniqueSummaryDiffs } from "./summary-diffs"
+// import { uniqueSummaryDiffs } from "./summary-diffs"  // suppressed (harmoniqs/amicode#733)
 
 export { TimelineRow, type SummaryDiff } from "./timeline-row"
 
@@ -290,15 +290,9 @@ export namespace Timeline {
 
     if (isActive && status === "retry") rows.push(new TimelineRow.Retry({ userMessageID: userMessage.id }))
 
-    const diffs = uniqueSummaryDiffs(userMessage.summary?.diffs)
-    if (diffs.length > 0 && (status === "idle" || !isActive)) {
-      rows.push(
-        new TimelineRow.DiffSummary({
-          userMessageID: userMessage.id,
-          diffs,
-        }),
-      )
-    }
+    // Per-message "Changed files" section suppressed (harmoniqs/amicode#733):
+    // redundant with the side-panel Files Changed tab, and the unfiltered
+    // snapshot diff leaks cross-session file changes during concurrent turns.
 
     if (error) {
       const data = error.data?.message