Allow SQLite import onto a freshly seeded Postgres instance.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/sqlite_to_postgres.py

@@ -149,12 +149,18 @@ def migrate(sqlite_path: Path, media_src: Path, media_dest: Path, replace: bool)
     stats: dict[str, tuple[int, int]] = {}
     try:
         existing = pg.execute("SELECT COUNT(*) FROM profiles").fetchone()[0]
+        seeds = pg.execute("SELECT COUNT(*) FROM tiers").fetchone()[0]
         if existing and not replace:
             raise SystemExit(
                 f"PostgreSQL already has {existing} profiles. Pass --replace after a probe copy, not on the only backup."
             )
-        if existing and replace:
+        if seeds and not replace:
-            print(f"Replacing {existing} existing Postgres profiles")
+            raise SystemExit(
+                "PostgreSQL already has platform seeds from startup. "
+                "Pass --replace to load a SQLite snapshot onto this instance (no user profiles yet is OK)."
+            )
+        if replace:
+            print(f"Replacing Postgres snapshot (profiles={existing}, seed_tiers={seeds})")
             for table in reversed(TABLES):
                 pg.execute(f"TRUNCATE TABLE {table} CASCADE")
 
@@ -179,6 +185,10 @@ def migrate(sqlite_path: Path, media_src: Path, media_dest: Path, replace: bool)
             count = pg.execute(f"SELECT COUNT(*) FROM {table}").fetchone()[0]
             print(f"  {table}: {len(rows)} → {count}")
             stats[table] = (len(rows), int(count))
+        pg.execute(
+            "INSERT INTO schema_migrations (id) VALUES (%s) ON CONFLICT (id) DO NOTHING",
+            ("022_postgres_runtime_baseline",),
+        )
         pg.commit()
     except Exception:
         pg.rollback()
@@ -195,6 +205,9 @@ def verify(stats: dict[str, tuple[int, int]]) -> None:
     failed = False
     print("\nVerification")
     for table, (src, dest) in stats.items():
+        if table == "schema_migrations" and dest == src + 1:
+            print(f"  ok       {table:36} sqlite={src:5} postgres={dest:5} (incl. 022)")
+            continue
         mark = "ok" if src == dest else "MISMATCH"
         if src != dest:
             failed = True