cleanup(session): isolate trajectory inspection

packages/client/ui-trajectory/src/client/TrajectoryTable.tsx

@@ -591,12 +591,9 @@ function messageOriginLabel(source: unknown): string {
 function MessageOrigin({ record }: { record: TableRecord }) {
   const source = record.cell.messageSource
   if (source === undefined) return <p className={css.noPayload}>Origin not recorded</p>
-  const sourceRoot = typeof source === 'object' && source !== null
+  const data = typeof source === 'object' && source !== null
     ? source
     : { value: source }
-  const data = record.cell.messageMeta === undefined
-    ? sourceRoot
-    : { source, meta: record.cell.messageMeta }
   return (
     <JsonTree
       data={data}

packages/client/ui-trajectory/src/client/layout.ts

@@ -317,7 +317,6 @@ export function deriveTrajectoryLayout(input: TrajectoryLayoutInput): readonly T
           index: ++index,
           kind: 'user',
           ...inputCellDetail(node),
-          ...(node.meta === undefined ? {} : { messageMeta: node.meta }),
           opensTurn: node.kind === 'user',
         },
       })

packages/client/ui-trajectory/src/client/trajectory-record.ts

@@ -47,7 +47,6 @@ export interface TrajectoryCellProps extends HTMLAttributes<HTMLDivElement> {
   /** Producer provenance from a user-role message or context injection. */
   messageSource?: unknown
   /** Producer-owned model-hidden metadata carried beside the message source. */
-  messageMeta?: unknown
   /** A separator-only anchor for an auxiliary request with no visible record. */
   requestOnly?: boolean
   /** Full request/message content for the details panel. */