Desktop app hides older turns although rollout JSONL retains message history

Problem

An existing desktop task displays only new exchanges. Closing and reopening the app does not restore earlier messages.

Read-only diagnostic evidence

• The task still exists in the sidebar.
• The task-history reader returns only today's turns and reports hasMore=false.
• The corresponding local rollout JSONL still contains older user and assistant messages, plus 17 older task_started events.
• The thread_history_1.sqlite thread_turns table contains only the 3 current turns for that task.
• The rollout contains a compacted record with replacement_history. Older entries share an initial timestamp. Whether this is causal is unconfirmed.

Expected

Previously visible conversation history should remain accessible, or a supported history rebuild/recovery should be available.

Environment

macOS desktop app, observed 2026-09-09. Exact app version not yet verified.

No database or rollout modifications attempted. Private transcript, task identifiers, business details and screenshots intentionally omitted. Please advise a supported way to rebuild the affected task's history projection without altering its conversation.

Start by tracing the task-history reader and its projection into thread_history_1.sqlite, especially the thread_turns table, then compare that behavior with the corresponding rollout JSONL and its replacement_history record. Done means older conversation turns remain accessible after reopening, or a supported history rebuild or recovery path is available without modifying the conversation.