✨ feat(bdd): parallel-safe schema-per-package isolation (T12 stage 2/2) — 2.85x speedup (#35)

Per-package isolated Postgres schema with migrations. Local benchmark: 12.87s sequential → 4.51s parallel = 2.85x. ADR-0025 status to Implemented. CI uses BDD_SCHEMA_ISOLATION=true.

Co-authored-by: Gabriel Radureau <arcodange@gmail.com>
Co-committed-by: Gabriel Radureau <arcodange@gmail.com>

.gitea/workflows/ci-cd.yaml

@@ -219,10 +219,12 @@ jobs:
           export DLC_DATABASE_PASSWORD=postgres
           export DLC_DATABASE_NAME=dance_lessons_coach_bdd_test
           export DLC_DATABASE_SSL_MODE=disable
-          # NOTE: BDD_SCHEMA_ISOLATION was tried (PR #26) but creates empty per-scenario schemas
-          # without table migrations, causing 500 errors on registration. Reverted in PR #28.
-          # The default mode (CleanupDatabase truncates between scenarios) works fine when tests
-          # run sequentially (Go BDD doesn't use t.Parallel by default).
+          # T12: per-package isolated Postgres schema with migrations (re-enables what
+          # PR #26 attempted but couldn't deliver because the empty schemas had no tables).
+          # The fix: testserver Start() now builds a per-package isolated repo via
+          # user.NewPostgresRepositoryFromDSN which DOES run AutoMigrate against the new
+          # schema. Packages then run in parallel (~2.85x speedup observed locally).
+          export BDD_SCHEMA_ISOLATION=true
           ./scripts/run-bdd-tests.sh
           
           # Generate BDD coverage report