Merge accepted local main into PR #184 working branch

src/core/native-messages.ts

@@ -563,8 +563,9 @@ export function toLlmMessages(messages: readonly AgentMessage[]): Message[] {
 	// THE COMPACTION CUT (owner round 14, 2026-10-05): the ACTIVE marker
 	// (the newest — chained compactions rule last) names the first kept
 	// message; everything before it is replaced by the marker's content
-	// (header + summary) rendered ONCE, up top. The marker itself is then
-	// skipped in place — it must never render twice. A cut naming a
+	// (header + summary) rendered ONCE, up top. All compaction markers
+	// in the retained tail are then skipped, including older summaries
+	// whose stored positions still lie after the cut. A cut naming a
 	// missing id degrades honestly (everything renders — never throw).
 	const lhMessages = messages as readonly LhMessage[];
 	const active = activeCompactionOf(lhMessages);
@@ -605,11 +606,10 @@ export function toLlmMessages(messages: readonly AgentMessage[]): Message[] {
 			// UI-only markers: plan blocks, and problem dismissals (the
 			// synthesized conclude pair carries the model's face).
 			if (marker.customType === "plan-block" || marker.customType === "problem-dismissed") continue;
-			// The ACTIVE compaction marker already rendered as the head —
-			// never twice. (Stale markers before the cut are unreachable; a
-			// marker whose cut could not resolve has no head and renders as
-			// its user text — honest degradation.)
-			if (marker.customType === "compaction" && head !== null && marker.id === active!.id) continue;
+			// The head supersedes every compaction marker, not only its own
+			// stored position. Without a resolved head, preserve the existing
+			// full-history fallback, including the summary text.
+			if (marker.customType === "compaction" && head !== null) continue;
 			out.push({
 				role: "user",
 				content: [{ type: "text", text: marker.content }],