Problem

Both mobile apps keep chat history purely in memory. On a cold open the transcript area is blank until the gateway responds, and when the gateway is unreachable (server asleep, network change, tunnel down) the apps show nothing at all — even for conversations the user was reading minutes earlier.

Proposal

Add a read-only local cache of sessions and recent messages on both platforms:

• Cache-first cold open: render the cached transcript immediately, fetch fresh history over it, and reconcile without a visible scroll jump.
• Offline read-only mode: when the gateway is unreachable, sessions and transcripts stay browsable with composing/actions disabled and a clear offline indicator.
• Cache is per-gateway, bounded (recent sessions + last N messages), and safe to drop/rebuild at any time — it is a cache, not a second source of truth. No offline send queue in scope.

Platform sketch: iOS/shared chat UI backed by SwiftData or SQLite; Android backed by Room. Read path stays gateway-first whenever connected.

Impact

Instant transcripts on launch and graceful behavior on flaky connections — the two most visible rough edges of the current foreground-first experience.