The previous implementation issued PRAGMA foreign_keys toggles inside
transactions (after tx.Begin()), but SQLite ignores pragmas once a
transaction is open with modernc.org/sqlite, making those calls no-ops.
This fix relocates the toggle to autocommit mode (db.Exec, not tx.Exec)
and limits it to only the three migrations that need it (0023/0024/0025),
which rebuild tables with incoming foreign keys (kind_assignments/
workout_type_paces reference workout_kinds; activities/sync_runs
reference sync_state).
The connection string now correctly restores ?_pragma=foreign_keys(1),
ensuring FK enforcement is ON by default for normal runtime operation
and during migrations that don't need the special handling.
Each affected migration now:
1. Disables FK in autocommit mode before starting its transaction
2. Runs the migration's CREATE/INSERT/DROP/RENAME sequence
3. Re-enables FK in autocommit mode after the transaction commits
All other migrations run normally with FK enforcement active throughout,
protecting against cascading deletions silently failing if a future
connection change causes FK enforcement to inadvertently remain off.
Added TestForeignKeyEnforcementPostMigration to verify FK is correctly
enforced after all migrations complete: valid FK references are accepted,
and invalid ones are rejected.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Schema-only step toward per-user profile isolation: profile/workout_kinds/
sync_state are rebuilt to drop their singleton constraints, activities/
sync_runs gain a nullable user_id column. Store methods are scoped in
later tasks.
