iOS app silently discards input drafts on in-conversation navigation

What happened

Typed a long message (~30 min of detailed body measurements I'd manually captured with a tape measure) into the chat input on the Claude Code iOS app. Navigated to a previous page in the same conversation, came back, the input was empty. No draft, no recovery, no warning before the navigation discarded it.

Platform

• Claude Code iOS app (iPhone)
• iOS version and app version: TBD

Expected

Either:
(a) Drafts persist locally scoped to conversation ID and restore on return (every modern iOS messaging app does this — Messages, Mail, Slack, Notes, etc. all preserve in-progress text across navigation)
(b) Confirmation prompt when navigating away with unsent input

Actual

Input silently destroyed. No "restore last draft" affordance anywhere in the app.

Impact

This isn't a paper cut. For users feeding Claude structured data (measurements, code, transcripts, anything tedious to re-type), 30+ min of work disappears with one back-tap. Low-trust UX that punishes exactly the kind of long, structured input Claude is best for. iOS users especially — mobile typing is slow and any data loss compounds.

Asks

1. Persist input drafts in local app storage, scoped to conversation ID, debounced ~500ms
2. Restore on conversation reopen / app foreground
3. Confirmation alert if user navigates away with > N chars of unsent input