T08: Drift schema mirroring the Room baseline

Three tables with CASCADE foreign keys, indices, WAL, and a real MigrationStrategy
from schema version 1. No destructive fallback, ever.

Two things needed deliberate handling. SQLite defaults foreign_keys to OFF and
Drift, unlike Room, does not enable it -- without the pragma every CASCADE is
decorative, so there is now a test that reads the pragma back. And Drift both
snake_cases columns and names row classes after tables; build.yaml sets
case_from_dart_to_sql: preserve so the schema stays column-for-column identical
to Room's, and @DataClassName keeps row types from colliding with the domain
models.

SchemaTest was instrumented and needed a device; the Drift version is a plain
unit test that runs in under a second with no emulator. 16 tests.

95 tests passing, analyze clean.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

build.yaml

@@ -0,0 +1,13 @@
+targets:
+  $default:
+    builders:
+      drift_dev:
+        options:
+          # Preserve Dart field names as SQL column names instead of snake_casing them.
+          #
+          # This keeps the schema column-for-column identical to the native app's Room
+          # schema (app/schemas/com.rippr.data.AppDatabase/2.json), which means the raw
+          # SQL in database.dart can stay byte-identical to the Kotlin DAO queries it was
+          # ported from -- much easier to review -- and leaves the door open to reading an
+          # old Room database file directly if an importer is ever wanted.
+          case_from_dart_to_sql: preserve