Data & Persistence

App-local model

Project contains a stable app-local ID, folder path, sessions, and current Git totals.
Session contains sidebar metadata, optional Pi session path, pending first prompt, pin/archive flags, and cached [TranscriptItem].
ConversationKey(projectID, sessionID) is the stable routing key for runtime state and callbacks.
These types and their persistence logic live together in AppModel.swift.

Pi owns canonical sessions: JSONL files under ~/.pi/agent/sessions/--<encoded-project-path>--/.
PiNative owns UI continuity: project bookmarks, selected project, pane settings, promotion settings, standalone chats, per-project session metadata, and cached transcripts in UserDefaults.
At startup, project sessions are merged by Pi session filePath: disk supplies current name/date/count; PiNative supplies stable local ID, pin/archive state, and cached transcript.
New sessions begin app-local with a pendingInitialPrompt; after new_session, Pi's resolved sessionFile is written back through a keyed callback.

The center pane can render immediately while Pi starts or hydrates.
A transient process/session error does not erase visible history.
Drafts and transcripts remain isolated because each chat keeps its own runtime model.
Transient startup failure notices are filtered before persistence.

Session-generation tokens reject stale async hydration results.
Process-generation tokens reject events from replaced clients.
Runtime callbacks capture ConversationKey, never ambient selection.
Archiving preserves session files and cache; runtime cleanup only removes the live process/model.