feat: add WonderQ admin backend

Add FastAPI admin/public API service, database setup, Docker deployment files, docs, and tests.

alembic/versions/0001_initial_schema.py

@@ -0,0 +1,32 @@
+"""Initial SQLAlchemy schema.
+
+Revision ID: 0001_initial_schema
+Revises:
+Create Date: 2026-06-30
+"""
+
+from alembic import context, op
+from sqlalchemy import inspect
+from app.database import Base
+from app import models  # noqa: F401
+
+
+revision = "0001_initial_schema"
+down_revision = None
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    bind = op.get_bind()
+    if context.is_offline_mode():
+        Base.metadata.create_all(bind=bind, checkfirst=False)
+        return
+    existing_tables = set(inspect(bind).get_table_names())
+    for table in Base.metadata.sorted_tables:
+        if table.name not in existing_tables:
+            table.create(bind)
+
+
+def downgrade() -> None:
+    Base.metadata.drop_all(bind=op.get_bind(), checkfirst=not context.is_offline_mode())