fix: Serverpod v4.0.4 and serverpod_offline_sync v0.0.10

serverpod_offline_sync v0.0.10 collects outbound changes in one
consistent snapshot, so a sync no longer fails on writes made while it
runs (upstream #84, #163), keeps checkpoints per author, so a device
clock moving backwards no longer stalls sync or resends data, and keeps
unique conflicts and foreign key defaults alike on every device. Its
tables and its messages are unchanged: no migration, and apps on v0.0.8
keep syncing. It needs Serverpod >=4.0.4 <4.1.0 (v4.0.4 is fixes only),
so the root overrides that held the workspace on one Serverpod go: each
package pins v4.0.4 itself. The generated code is identical under the
v4.0.4 CLI, which CI now uses.

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

@@ -154,7 +154,7 @@ A spaced-repetition learning app: studysets of flashcards, reviewed on an FSRS s
   - **The client's local migration** (in `halkyon_learn_client/lib/migrations/`, written by the same `create-migration`) creates the device's SQLite schema from the whole definition, so it also contains the server's own tables. Only the synced tables and the bookkeeping ever hold data on a device.
 - **Older apps** can't be made to update once published. Before the first sync of each launch the app asks whether the server still works with its build (`minimumAppBuild` in `instance.info()`, from `lib/src/instance/app_compatibility.dart` in the server; the build is the number after `+` in the app's version), and the sync engine refuses an app whose synced tables differ from the server's. Both end in `AppServerMismatchException` (`core/sync/`), and the app says so: a banner on Home and the Sync card in Settings. Raise `minimumAppBuild` in the commit that breaks older apps (an endpoint they call changes or goes), to the build of the first app that works again; a change to the synced tables needs no raise. Every release raises the build number.
 - **Where sync stands** is `SyncService.status` (syncing, the last sync that went through, the last failure; since the app started), which `SyncStatusBloc` (`core/sync/`, provided by `PersonApp`) hands to the trouble dot on the Settings cogs (on Home and Profile; no tab carries it), the Sync card in Settings and the banner on Home. Only the last outcome counts: one sync that goes through clears a failure. The Library's Refresh and pulling it down sync now (`syncAndWait`, which a pull's spinner waits on).
-- **Serverpod's version moves together with `serverpod_offline_sync`**, which pins Serverpod exactly: the root `pubspec.yaml` overrides the four core packages to the project's version. Upgrade Serverpod only together with those overrides and the CLI version CI generates code with (`SERVERPOD_VERSION` in `.forgejo/workflows/ci.yaml`), after reading the sync package's changelog.
+- **Serverpod's version moves together with `serverpod_offline_sync`**, which allows only a narrow range of Serverpod (v0.0.10: `>=4.0.4 <4.1.0`; v0.0.8 pinned v4.0.0 exactly, which the root `pubspec.yaml` overrode until 2026-10-09). Every package pins Serverpod's packages to one version: upgrade them all together with the sync packages and the CLI version CI generates code with (`SERVERPOD_VERSION` in `.forgejo/workflows/ci.yaml`), after reading the sync package's changelog. Never override a version the sync package doesn't allow without checking what changed in `serverpod_database`, which it builds on.
 - **The source-code link**: both licences require offering the source of what an instance runs to the people who use it. `instance.info().sourceCodeUrl` names it (the operator's `SOURCE_URL`, else this project's repository) and the app's About dialog shows it next to the licences and every package's notice. Keep it working when changing the dialog or the endpoint.
 - **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. Scheduling a future call always adds an entry, so the server cancels the previous one by its identifier first.