scripts/migrate_legacy_data.py copies rows from the legacy locationRecorder.db
/ pooRecorder.db into the unified app DB's location / poo_records tables using
ATTACH + INSERT OR IGNORE (idempotent via PK-conflict skip; explicit columns,
never SELECT *). After copy it reconciles every source row against the target
and raises / exits non-zero on any shortfall. Missing legacy files are a safe
no-op (skipped); --dry-run writes nothing. Not part of the Alembic chain; run
manually once at cut-over. Never deletes or overwrites any file.
Validated end-to-end on copies of the real production DBs: dry-run reported
75103 location + 874 poo rows and wrote nothing; the real run copied all rows
with reconciliation passing; a second run copied 0 (idempotent).
Add alembic_app revision 20260611_06_merge_location_poo_tables that builds
empty location and poo_records tables (REAL float columns, matching the
production schema and the adopt scripts' EXPECTED_*_TABLE_INFO constants).
Update APP_BASELINE_REVISION to the new head. Schema-only; data migration
is handled separately by scripts/migrate_legacy_data.py (M1-T02).
tliu93