fix(web): omit plan transcript rows

web/src/structuredRender.ts

@@ -367,14 +367,33 @@ function buildApprovalRow(row: TranscriptRow, approval: ApprovalRowState): HTMLE
   return wrap;
 }
 
-/** Build the DOM for one transcript row. `approval` is consulted only for an
- *  `approval` row; tool expansion is supplied and reported explicitly. */
+/** Build the DOM for one transcript row, or `null` for a plan shown only in
+ *  the rail. `approval` is consulted only for an `approval` row; tool
+ *  expansion is supplied and reported explicitly. */
+export function buildTranscriptRow(
+  row: TranscriptRow & { kind: "plan" },
+  approval?: ApprovalRowState,
+  toolExpanded?: boolean,
+  onToolExpandedChange?: (expanded: boolean) => void,
+): null;
+export function buildTranscriptRow(
+  row: TranscriptRow & { kind: Exclude<TranscriptRow["kind"], "plan"> },
+  approval?: ApprovalRowState,
+  toolExpanded?: boolean,
+  onToolExpandedChange?: (expanded: boolean) => void,
+): HTMLElement;
+export function buildTranscriptRow(
+  row: TranscriptRow,
+  approval?: ApprovalRowState,
+  toolExpanded?: boolean,
+  onToolExpandedChange?: (expanded: boolean) => void,
+): HTMLElement | null;
 export function buildTranscriptRow(
   row: TranscriptRow,
   approval?: ApprovalRowState,
   toolExpanded = false,
   onToolExpandedChange?: (expanded: boolean) => void,
-): HTMLElement {
+): HTMLElement | null {
   let built: HTMLElement;
   switch (row.kind) {
     case "user":
@@ -393,6 +412,8 @@ export function buildTranscriptRow(
     case "approval":
       built = buildApprovalRow(row, approval ?? { pending: false, onDecide: () => Promise.resolve() });
       break;
+    case "plan":
+      return null;
     default:
       built = buildPlainRow(row);
       break;