fix(app): coming back with a field focused brings its keyboard back

Leaving the app while its keyboard was moving and coming back left the
screen pushed up as if the keyboard were there, the field focused and
no keyboard showing: Flutter gives the window back the keyboard's
height then (flutter#191156, open). Coming back with a field focused now
brings its keyboard back, as other apps on Android do, so the height is
the keyboard's again.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01MMm7usAo6q9ZZRoPkWjoxi
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

AGENTS.md

@@ -168,6 +168,7 @@ A spaced-repetition learning app: studysets of flashcards, reviewed on an FSRS s
 - **Reports and suggestions** (ADR 0005, stage 4, rule 11): `feedback_thread` (a report or suggestion: `publicationId` and `kind` columns, everything else in its payload: what it is about by release item id and version, a report's category, the text, a suggestion's proposed payload and the files it names), `feedback_message` (replies) and `feedback_decision` (an author's closed, reopened, hidden, shown, accepted, declined; the latest of each pair stands) are synced tables each person writes in their own space; a thread or reply names its thread by id only, as it may be another person's. `gatherFeedback` (`lib/src/feedback/`) assembles them for `FeedbackEndpoint.threadsOf` (`requireLogin`: public) and `InboxEndpoint` (`identified`: the inbox, unseen counts, `markSeen`, `block`, `file`) and decides what counts as it reads (see the ADR), since a modified app could write anything. `feedback_block` and `feedback_seen` are server-only; `deletePerson` deletes both. A release's commit credits the writers of suggestions accepted since the last (`Co-authored-by`). In the app (`feature/feedback/`): the card's Report sheet offers "Send to the author too" on a card from a release; a copy's ⋮ menu reports the studyset and lists its threads, as Explore's summary does; the editors of cards (⋮), notes and steps (app bar) suggest to the author (refused under "no derivatives"); the Inbox is in the Profile tab, with a count on the tab (`InboxCountBloc`, refreshed at start and whenever the inbox is read or acted on; no timer); a thread's sheet shows a suggestion beside the author's own item, its replies, and the author's decisions. Accepting writes the proposed content as the author's own revision (`FeedbackRepository.accept`), the writer's files fetched by hash.
 - **Deleting a person** goes through `deletePerson` (`lib/src/auth/account.dart`), in one transaction and in ADR 0001 rule 6's order: their sessions end first (a device with a valid session would re-upload everything), then their space goes with all its content through the foreign keys, then the person with their identities. `AccountEndpoint.delete` deletes the caller; the app also calls it when an anonymous account is given up (signed out of, or switched away from to GitHub), since nobody could ever sign into it again.
 - **Pruning**: `PruningFutureCall` deletes anonymous people unused for 90 days, daily, scheduled when the server starts; and hourly the notes Serverpod's rate limit makes of anonymous sign-ups (`serverpod_auth_idp_rate_limited_request_attempt`, each with the IP address it came from) once the limit's hour is past (`forgetOldSignUpAttempts`): Serverpod deletes them only for email sign-in, so they would otherwise stay for good, and the privacy page says the instance keeps no IP addresses beyond that. Scheduling a future call always adds an entry, so the server cancels the previous one by its identifier first.
+- **Coming back with a field focused brings its keyboard back** (`KeyboardBackOnResume` around the app): Flutter (v3.47.5) gives the window back the keyboard's height after the app was left while the keyboard moved, with no keyboard showing, which left screens pushed up ([flutter#191156](https://github.com/flutter/flutter/issues/191156), open). Remove it once that is fixed.
 - **One person's data per device**: `PersonFolders` wipes every other person's folder when a person's data opens: their sessions ended on this device. Opening waits for the previous person's database to close.
 - **Session logs are not persisted** (`persistentEnabled: false` in every run mode) for privacy. Don't re-enable them.
 - **Secrets** live in `halkyon_learn_server/config/passwords.yaml` (git-ignored). Never change `serverSideSessionKeyHashPepper`: it would sign everyone out, and anonymous accounts can't sign back in.