Add admin user seeding functionality and corresponding tests

backend/app/db.py

@@ -75,3 +75,26 @@ def _run_migrations(conn: duckdb.DuckDBPyConnection) -> None:
             created_at   TIMESTAMP DEFAULT now()
         )
     """)
+    _seed_admin(conn)
+
+
+def _seed_admin(conn: duckdb.DuckDBPyConnection) -> None:
+    """Insert the default admin user if it doesn't already exist."""
+    from passlib.context import CryptContext
+    _pwd = CryptContext(schemes=["bcrypt"], deprecated="auto")
+
+    email = os.getenv("ADMIN_EMAIL", "ai@allucanget.biz")
+    password = os.getenv("ADMIN_PASSWORD", "admin123")
+
+    existing = conn.execute(
+        "SELECT id FROM users WHERE email = ?", [email]
+    ).fetchone()
+    if existing is None:
+        password_hash = _pwd.hash(password)
+        conn.execute(
+            """
+            INSERT INTO users (email, password_hash, role)
+            VALUES (?, ?, 'admin')
+            """,
+            [email, password_hash],
+        )

backend/tests/test_db.py

@@ -192,3 +192,39 @@ async def test_write_lock_serialises_concurrent_writes():
     # Each writer's start and end must be adjacent (no interleaving)
     assert order.index("A-start") + 1 == order.index("A-end") or \
         order.index("B-start") + 1 == order.index("B-end")
+
+
+# ---------------------------------------------------------------------------
+# Admin seed user
+# ---------------------------------------------------------------------------
+
+def test_seed_admin_user_created_on_init():
+    import os
+    conn = db_module.init_db(":memory:")
+    row = conn.execute(
+        "SELECT email, role FROM users WHERE email = 'ai@allucanget.biz'"
+    ).fetchone()
+    assert row is not None
+    assert row[0] == "ai@allucanget.biz"
+    assert row[1] == "admin"
+
+
+def test_seed_admin_is_idempotent():
+    conn = db_module.init_db(":memory:")
+    # Simulate re-running seed (second init_db call reuses connection, so call _seed_admin directly)
+    db_module._seed_admin(conn)
+    count = conn.execute(
+        "SELECT COUNT(*) FROM users WHERE email = 'ai@allucanget.biz'"
+    ).fetchone()[0]
+    assert count == 1
+
+
+def test_seed_admin_email_env_override(monkeypatch):
+    monkeypatch.setenv("ADMIN_EMAIL", "custom@example.com")
+    monkeypatch.setenv("ADMIN_PASSWORD", "custompass")
+    conn = db_module.init_db(":memory:")
+    row = conn.execute(
+        "SELECT email, role FROM users WHERE email = 'custom@example.com'"
+    ).fetchone()
+    assert row is not None
+    assert row[1] == "admin"