docs(11.1-04): log lagoon gaps found while writing the Database pages

- lagoon.Validate reports numeric min failures with the max message
- the lagoon README callback example sorts after the after-commit flush,
  and the pivot Preload ordering claim does not hold

.planning/todos/pending/lagoon-readme-after-commit-callback-order.md

@@ -0,0 +1,12 @@
+---
+title: lagoon README registers an after-commit GORM callback that can sort after the flush
+date: 2026-09-30
+priority: high
+area: summercms.go lagoon
+---
+
+The `lagoon.OnDatabase` example in `modules/lagoon/README.md` registers its create callback with `After("gorm:after_create")` and calls `lagoon.AfterCommit` from it. GORM sorts that callback after `lagoon:after_commit` (itself `After("gorm:commit_or_rollback_transaction")`), so the work is buffered after the buffer was flushed and never runs, with no error or log. A docs test reproduced it: the same callback registered with `After("gorm:create").Before("gorm:commit_or_rollback_transaction")` runs as expected.
+
+Found while writing `docs/database/transactions.md` (Phase 11.1 plan 04). The page registers the callback before GORM's commit callback and says why.
+
+Suggested fix: change the README example to register before `gorm:commit_or_rollback_transaction`, and consider making `lagoon.AfterCommit` warn when it buffers work on a statement whose `lagoon:after_commit` callback has already run. The README was read-only in plan 11.1-04 (Phase 11 gap plan 11-08 owned it). While there, correct the `lagoon.RegisterJoinTable` comment and README line that say pivot reads use `Preload(field)` plus `.Order(...)` on the pivot's columns: GORM preloads many-to-many targets in a query without the join table, so ordering by a pivot column there fails with "missing FROM-clause entry"; an explicit join does work.