fix(web): keep compaction status semantic row singular

apps/web/src/features/transcript/TranscriptRows.tsx

@@ -609,15 +609,19 @@ function UnknownEntryRow({
 function WorkingRow({
   row,
   nowMs,
+  ghost,
 }: {
   readonly row: Extract<TranscriptRow, { kind: "working" }>;
   readonly nowMs: number;
+  readonly ghost: boolean;
 }) {
   const compacting = row.activity === "preparing-context";
   return (
     <div
       className="flex items-center gap-2 py-3 text-status-working text-xs"
-      data-transcript-status={compacting ? "compacting-context" : "working"}
+      // The live status is a singleton: a paint-only ghost copy (cold-mount
+      // overlay) must never duplicate the semantic lifecycle hook.
+      data-transcript-status={ghost ? undefined : compacting ? "compacting-context" : "working"}
     >
       <LoaderCircle
         aria-hidden="true"
@@ -653,12 +657,19 @@ export const TranscriptRowContent = memo(function TranscriptRowContent({
   nowMs,
   imageSource,
   toolHost,
+  ghost = false,
 }: {
   readonly row: TranscriptRow;
   /** Elapsed-label time base from the session runtime snapshot. */
   readonly nowMs: number;
   readonly imageSource: TranscriptImageSource;
   readonly toolHost?: ToolRenderHost | undefined;
+  /**
+   * Paint-only duplicate of a row (the cold-mount overlay's warm copy).
+   * A ghost renders pixel-identical but never carries singleton semantic
+   * hooks — the live transcript copy is the only semantic instance.
+   */
+  readonly ghost?: boolean | undefined;
 }) {
   switch (row.kind) {
     case "message":
@@ -672,6 +683,6 @@ export const TranscriptRowContent = memo(function TranscriptRowContent({
     case "unknown-entry":
       return <UnknownEntryRow row={row} />;
     case "working":
-      return <WorkingRow nowMs={nowMs} row={row} />;
+      return <WorkingRow ghost={ghost} nowMs={nowMs} row={row} />;
   }
 });

apps/web/src/features/transcript/TranscriptTimeline.tsx

@@ -370,6 +370,7 @@ export const TranscriptTimeline = memo(function TranscriptTimeline({
                   key={row.id}
                 >
                   <TranscriptRowContent
+                    ghost
                     imageSource={imageSource}
                     nowMs={nowMs}
                     row={row}

apps/web/test/compaction-status.test.tsx

@@ -19,11 +19,20 @@ const IMAGE_SOURCE: TranscriptImageSource = {
   dispose: () => undefined,
 };
 
-function renderWorkingRow(projection: TranscriptProjection, nowMs: number): string | null {
+function renderWorkingRow(
+  projection: TranscriptProjection,
+  nowMs: number,
+  options?: { readonly ghost?: boolean },
+): string | null {
   const row = deriveTranscriptRows(projection).find((candidate) => candidate.kind === "working");
   if (row?.kind !== "working") return null;
   return renderToStaticMarkup(
-    <TranscriptRowContent imageSource={IMAGE_SOURCE} nowMs={nowMs} row={row} />,
+    <TranscriptRowContent
+      ghost={options?.ghost ?? false}
+      imageSource={IMAGE_SOURCE}
+      nowMs={nowMs}
+      row={row}
+    />,
   );
 }
 
@@ -87,4 +96,27 @@ describe("compaction transcript status", () => {
     expect(markup).toContain("4s");
     expect(markup).not.toContain("Compacting context");
   });
+
+  it("keeps the lifecycle hook off paint-only ghost copies so one semantic row exists", () => {
+    const factory = new FrameFactory({ host: "host", session: "session", epoch: "epoch" });
+    let projection = projectionWithSnapshot(factory);
+    projection = reduceTranscript(
+      projection,
+      factory.event({
+        type: "compaction.start",
+        reason: "pending_prompt_size",
+        at: "2026-07-15T20:00:01Z",
+      }),
+    );
+
+    const nowMs = Date.parse("2026-07-15T20:00:06Z");
+    const ghost = renderWorkingRow(projection, nowMs, { ghost: true });
+    expect(ghost).not.toBeNull();
+    // The ghost paints the same copy but never duplicates the semantic hook.
+    expect(ghost).not.toContain("data-transcript-status");
+    expect(ghost).toContain("Compacting context for ");
+    expect(renderWorkingRow(projection, nowMs)).toContain(
+      'data-transcript-status="compacting-context"',
+    );
+  });
 });

provenance/t3code/imports/f2-transcript-20260711.json

@@ -9,7 +9,7 @@
       "sourceBlobSha": "1a4dc6b689558a9f8d834c12d7ecb2bb64e0d7c8",
       "targetPath": "apps/web/src/features/transcript/TranscriptTimeline.tsx",
       "classification": "adapted",
-      "checksum": "sha256:1f302713aebae1d70fe4509a2107a35fa4827e47016968976f322b345446b420"
+      "checksum": "sha256:83148bec99a0d57d47a5f239d0b2dc904b8696315ef6d0e7149d773234a12c7f"
     },
     {
       "sourcePath": "apps/web/src/components/chat/MessagesTimeline.tsx",
@@ -23,7 +23,7 @@
       "sourceBlobSha": "1a4dc6b689558a9f8d834c12d7ecb2bb64e0d7c8",
       "targetPath": "apps/web/src/features/transcript/TranscriptRows.tsx",
       "classification": "adapted",
-      "checksum": "sha256:fd24741fc543e280d2d03295da35d246ece68c6614aa17903ebc53a9bb1e3ad4"
+      "checksum": "sha256:e8fe7580c871464d2389099468c786cc9c90b669171b641e27223e7894d57784"
     },
     {
       "sourcePath": "packages/shared/src/searchRanking.ts;apps/web/src/components/chat/composerSlashCommandSearch.ts",