fix: the practice live-view law — live is positive evidence; absorb custom markers

The thinking-submission incident (owner report, 2026-10-05): two spinners
sandwiching the submitted thinking card, and the card doubling once tokens
flowed. Records on disk were clean — both bugs were live-view-only.

- view.ts LIVE IS POSITIVE EVIDENCE (owner ruling): a tool call renders
  live (input-streaming) ONLY when its own message is streaming THIS turn
  (streamingIds) — session busyness can never resurrect a settled call.
  The pose turn's problem call kept flipping to a mid-transcript spinner
  because the fallback keyed on live.inFlight. applyResultTo's placeholder
  fork now also MARKS the settled ack (input-available) instead of leaving
  the guessed state standing. Live cards now sit at the bottom by
  construction, never mid-transcript.
- session-core.ts absorbed(): the custom role gets its identity key
  (customType + details deep-equal) — the optimistic thinking marker is
  dropped when the write-ahead's server copy lands, so the +400ms
  adoption window can no longer double the card. Total over roles; types
  that never appear optimistically never reach the branch.

Pinned: settled problem never live mid-turn; this turn's streaming call
stays shimmer; dangling-settled is input-available; absorbed by
customType+details (different details = different submission); model-level
adoption keeps exactly one marker.

components/session-core.ts

@@ -23,6 +23,7 @@ import {
 	newUserMessage,
 	projectView,
 	type ChatInput,
+	type LhMarkerMessage,
 	type LhMessage,
 	type LhViewMessage,
 	type LiveExecution,
@@ -134,9 +135,30 @@ export function absorbed(m: LhMessage, record: readonly LhMessage[]): boolean {
 				(r as ToolResultMessage).toolCallId === toolCallId,
 		);
 	}
+	if (role === "custom") {
+		// Markers (the thinking submission, 2026-10-05 — the doubled-card
+		// bug: the optimistic practice-thinking card was never absorbed, so
+		// the adoption window rendered it beside the write-ahead's server
+		// copy for the whole turn). TOTAL over roles by identity key — a
+		// marker is itself when its customType AND structured details match;
+		// types that never appear optimistically simply never reach here.
+		const marker = m as LhMarkerMessage;
+		return record.some(
+			(r) =>
+				(r as { role?: string }).role === "custom" &&
+				(r as LhMarkerMessage).customType === marker.customType &&
+				sameDetails((r as LhMarkerMessage).details, marker.details),
+		);
+	}
 	return false;
 }
 
+/** Structural deep-equal for marker details (JSON-stable payloads — the
+ *  constructors mint plain data). */
+function sameDetails(a: unknown, b: unknown): boolean {
+	return JSON.stringify(a) === JSON.stringify(b);
+}
+
 export interface SessionState {
 	messages: LhViewMessage[];
 	nativeMessages: LhMessage[];