docs(05): create phase plan

.planning/phases/05-data-layer-full-fidelity/05-05-PLAN.md

@@ -145,7 +145,10 @@ func Status(gdb *gorm.DB, plugins []party.Plugin) ([]StatusRow, error)
   <action>
     Reproduce the exact method RESEARCH.md documents as already verified this research session: run a scratch `postgres:16-alpine` container, run the real PHP app's `php artisan winter:up` against it (from the sibling PHP repo at `/media/nvme/dev/golem15/fonoteka`), then `pg_dump --schema-only` filtered to `golem15_fonoteka_*`, `system_files`, `users`, `golem15_user_organisations` tables, normalizing owner/privilege noise (`--no-owner --no-privileges`). Commit the resulting SQL as `fonoteka.go/parity/testdata/php_schema_snapshot.sql` — this is a one-time, offline generation step; CI/tests never need PHP installed.
 
-    Create `parity/schema_diff_test.go`'s `TestSchemaMatchesPHPSnapshot`: spin up a dedicated ICU pl-PL database (same pattern as `migrate_test.go`'s `TestRollbackLastIsolatesFonoteka`), run `lagoon.Migrate(gdb, plugins)` for both `golem15.user` and `golem15.fonoteka` plus the framework's `system_files` set, then load the committed snapshot into a second dedicated database (`psql < php_schema_snapshot.sql` via `exec.Command` or by parsing the SQL directly), and diff both databases' `information_schema.columns`/`information_schema.table_constraints`/`pg_indexes` for the shared table set, failing on any unexplained difference (missing table, missing column, type mismatch, missing/extra unique or FK constraint). Keep a small, explicitly commented allow-list `var allowedDiffs = map[string]string{...}` for genuinely intended differences (e.g. `golem15_fonoteka_settings` existing in the Go schema with no PHP equivalent, since Settings uses a dedicated table per the resolved open question rather than Winter's generic `system_settings` — document exactly why each allow-listed entry exists, per the scope_reduction/gap-handling discipline: this is a deliberate decision, not a silently-tolerated gap). Run `lagoon.Migrate` against the production plugins only (`golem15.user` + `golem15.fonoteka` + framework `system_files`). Do not activate the DATA-11 fixture plugin in this test. Do not add `demo_extension_note` (or any fixture-only column) to `allowedDiffs` — that column must not exist on the production schema (D-02).
+    Create `parity/schema_diff_test.go`'s `TestSchemaMatchesPHPSnapshot`: spin up a dedicated ICU pl-PL database (same pattern as `migrate_test.go`'s `TestRollbackLastIsolatesFonoteka`), run `lagoon.Migrate(gdb, plugins)` for both `golem15.user` and `golem15.fonoteka` plus the framework's `system_files` set, then load the committed snapshot into a second dedicated database (`psql < php_schema_snapshot.sql` via `exec.Command` or by parsing the SQL directly), and diff both databases' `information_schema.columns`/`information_schema.table_constraints`/`pg_indexes` for the shared table set, failing on any unexplained difference (missing table, missing column, type mismatch, missing/extra unique or FK constraint). Keep a small, explicitly commented allow-list `var allowedDiffs = map[string]string{...}` for genuinely intended differences. Required entries (each with an inline comment naming the decision):
+      1. `golem15_fonoteka_settings` existing in the Go schema with no PHP equivalent, since Settings uses a dedicated table per the resolved open question rather than Winter's generic `system_settings`.
+      2. `users` table column-count gap: the PHP snapshot dumps the full 52-column Winter `users` table; Go keeps the Phase-3 stub (no `organisation_id`/`organisation_role`/membership columns). This is intended. Cite the user-confirmed no-`widen_users` decision (D-03 deviation, deferred to Phase 7 AUTH-02). Do NOT add a `widen_users` migration to close this diff — that would contradict the confirmed decision.
+      Document exactly why each allow-listed entry exists, per the scope_reduction/gap-handling discipline: this is a deliberate decision, not a silently-tolerated gap. Run `lagoon.Migrate` against the production plugins only (`golem15.user` + `golem15.fonoteka` + framework `system_files`). Do not activate the DATA-11 fixture plugin in this test. Do not add `demo_extension_note` (or any fixture-only column) to `allowedDiffs` — that column must not exist on the production schema (D-02).
   </action>
   <verify>
     <automated>cd /media/nvme/dev/golem15/summercms.io/summercms/fonoteka.go && go vet ./parity/... && go test ./parity/... -run TestSchemaMatchesPHPSnapshot</automated>
@@ -153,7 +156,7 @@ func Status(gdb *gorm.DB, plugins []party.Plugin) ([]StatusRow, error)
   <acceptance_criteria>
     - `fonoteka.go/parity/testdata/php_schema_snapshot.sql` is committed and non-empty, covering all 25 Fonoteka tables plus `system_files`/`users`/`golem15_user_organisations`.
     - `TestSchemaMatchesPHPSnapshot` fails if a column is deliberately dropped from a migration in a scratch branch (spot-check this manually during development, then restore before finishing).
-    - Every entry in `allowedDiffs` has an inline comment naming the specific decision (D-01/D-02/RESEARCH Open Question 2) that justifies it.
+    - Every entry in `allowedDiffs` has an inline comment naming the specific decision that justifies it: `golem15_fonoteka_settings` cites RESEARCH Open Question 2; the `users` table column-count gap cites the user-confirmed no-`widen_users` decision (D-03 deviation, deferred to Phase 7 AUTH-02). Do not close the `users` gap with a `widen_users` migration.
     - `grep -n "demo_extension_note" fonoteka.go/parity/schema_diff_test.go fonoteka.go/plugins/golem15/fonoteka/updates` returns no matches (production schema and its allow-list never mention the fixture column).
   </acceptance_criteria>
   <done>The committed PHP schema snapshot exists and `TestSchemaMatchesPHPSnapshot` proves the full Go schema matches it modulo a small, justified, commented allow-list.</done>