feat(phase1): Complete development environment configuration

- Configure Alembic for database migrations with initial schema
- Fix base.py to use lazy loading for async engine (avoids import-time issues)
- Change AI model from sonnet to haiku (claude-3-haiku-20240307)
- Fix pytest version compatibility with pytest-asyncio
- Add frontend package-lock.json

Phase 1 tasks completed:
- F1.1: Development environment (Docker, Node.js 20, Python 3.12, venv)
- F1.2: PostgreSQL with 8 categories seeded
- F1.3: Redis connection verified
- F1.4: Anthropic API configured and tested
- F1.5: Backend server + WebSocket verified

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/alembic.ini

@@ -0,0 +1,42 @@
+[alembic]
+script_location = alembic
+prepend_sys_path = .
+version_path_separator = os
+
+sqlalchemy.url = postgresql://trivia:trivia@localhost:5432/trivia
+
+[post_write_hooks]
+
+[loggers]
+keys = root,sqlalchemy,alembic
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARN
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = WARN
+handlers =
+qualname = sqlalchemy.engine
+
+[logger_alembic]
+level = INFO
+handlers =
+qualname = alembic
+
+[handler_console]
+class = StreamHandler
+args = (sys.stderr,)
+level = NOTSET
+formatter = generic
+
+[formatter_generic]
+format = %(levelname)-5.5s [%(name)s] %(message)s
+datefmt = %H:%M:%S

backend/alembic/env.py

@@ -0,0 +1,52 @@
+from logging.config import fileConfig
+from sqlalchemy import engine_from_config, pool
+from alembic import context
+import sys
+import os
+
+# Add the backend directory to the path
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+from app.models.base import Base
+from app.models import Category, Question, GameSession, GameEvent, Admin
+
+config = context.config
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+target_metadata = Base.metadata
+
+
+def run_migrations_offline() -> None:
+    url = config.get_main_option("sqlalchemy.url")
+    context.configure(
+        url=url,
+        target_metadata=target_metadata,
+        literal_binds=True,
+        dialect_opts={"paramstyle": "named"},
+    )
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+def run_migrations_online() -> None:
+    connectable = engine_from_config(
+        config.get_section(config.config_ini_section, {}),
+        prefix="sqlalchemy.",
+        poolclass=pool.NullPool,
+    )
+
+    with connectable.connect() as connection:
+        context.configure(
+            connection=connection, target_metadata=target_metadata
+        )
+
+        with context.begin_transaction():
+            context.run_migrations()
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()

backend/alembic/script.py.mako

@@ -0,0 +1,26 @@
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+${imports if imports else ""}
+
+# revision identifiers, used by Alembic.
+revision: str = ${repr(up_revision)}
+down_revision: Union[str, None] = ${repr(down_revision)}
+branch_labels: Union[str, Sequence[str], None] = ${repr(branch_labels)}
+depends_on: Union[str, Sequence[str], None] = ${repr(depends_on)}
+
+
+def upgrade() -> None:
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade() -> None:
+    ${downgrades if downgrades else "pass"}

backend/alembic/versions/65d30b7402cf_initial_schema.py

@@ -0,0 +1,108 @@
+"""Initial schema
+
+Revision ID: 65d30b7402cf
+Revises: 
+Create Date: 2026-01-26 08:04:31.725883
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = '65d30b7402cf'
+down_revision: Union[str, None] = None
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table('admins',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('username', sa.String(length=100), nullable=False),
+    sa.Column('password_hash', sa.String(length=255), nullable=False),
+    sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('now()'), nullable=True),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_admins_id'), 'admins', ['id'], unique=False)
+    op.create_index(op.f('ix_admins_username'), 'admins', ['username'], unique=True)
+    op.create_table('categories',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('name', sa.String(length=100), nullable=False),
+    sa.Column('icon', sa.String(length=50), nullable=True),
+    sa.Column('color', sa.String(length=7), nullable=True),
+    sa.PrimaryKeyConstraint('id'),
+    sa.UniqueConstraint('name')
+    )
+    op.create_index(op.f('ix_categories_id'), 'categories', ['id'], unique=False)
+    op.create_table('game_sessions',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('room_code', sa.String(length=6), nullable=False),
+    sa.Column('status', sa.String(length=20), nullable=True),
+    sa.Column('team_a_score', sa.Integer(), nullable=True),
+    sa.Column('team_b_score', sa.Integer(), nullable=True),
+    sa.Column('current_team', sa.String(length=1), nullable=True),
+    sa.Column('questions_used', sa.ARRAY(sa.Integer()), nullable=True),
+    sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('now()'), nullable=True),
+    sa.Column('finished_at', sa.DateTime(timezone=True), nullable=True),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_game_sessions_id'), 'game_sessions', ['id'], unique=False)
+    op.create_index(op.f('ix_game_sessions_room_code'), 'game_sessions', ['room_code'], unique=True)
+    op.create_table('questions',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('category_id', sa.Integer(), nullable=False),
+    sa.Column('question_text', sa.Text(), nullable=False),
+    sa.Column('correct_answer', sa.String(length=500), nullable=False),
+    sa.Column('alt_answers', sa.ARRAY(sa.String()), nullable=True),
+    sa.Column('difficulty', sa.Integer(), nullable=False),
+    sa.Column('points', sa.Integer(), nullable=False),
+    sa.Column('time_seconds', sa.Integer(), nullable=False),
+    sa.Column('date_active', sa.Date(), nullable=True),
+    sa.Column('status', sa.String(length=20), nullable=True),
+    sa.Column('fun_fact', sa.Text(), nullable=True),
+    sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('now()'), nullable=True),
+    sa.ForeignKeyConstraint(['category_id'], ['categories.id'], ),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_questions_date_active'), 'questions', ['date_active'], unique=False)
+    op.create_index(op.f('ix_questions_id'), 'questions', ['id'], unique=False)
+    op.create_table('game_events',
+    sa.Column('id', sa.Integer(), nullable=False),
+    sa.Column('session_id', sa.Integer(), nullable=False),
+    sa.Column('event_type', sa.String(length=50), nullable=False),
+    sa.Column('player_name', sa.String(length=100), nullable=True),
+    sa.Column('team', sa.String(length=1), nullable=True),
+    sa.Column('question_id', sa.Integer(), nullable=True),
+    sa.Column('answer_given', sa.Text(), nullable=True),
+    sa.Column('was_correct', sa.Boolean(), nullable=True),
+    sa.Column('was_steal', sa.Boolean(), nullable=True),
+    sa.Column('points_earned', sa.Integer(), nullable=True),
+    sa.Column('timestamp', sa.DateTime(timezone=True), server_default=sa.text('now()'), nullable=True),
+    sa.ForeignKeyConstraint(['question_id'], ['questions.id'], ),
+    sa.ForeignKeyConstraint(['session_id'], ['game_sessions.id'], ),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_game_events_id'), 'game_events', ['id'], unique=False)
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_index(op.f('ix_game_events_id'), table_name='game_events')
+    op.drop_table('game_events')
+    op.drop_index(op.f('ix_questions_id'), table_name='questions')
+    op.drop_index(op.f('ix_questions_date_active'), table_name='questions')
+    op.drop_table('questions')
+    op.drop_index(op.f('ix_game_sessions_room_code'), table_name='game_sessions')
+    op.drop_index(op.f('ix_game_sessions_id'), table_name='game_sessions')
+    op.drop_table('game_sessions')
+    op.drop_index(op.f('ix_categories_id'), table_name='categories')
+    op.drop_table('categories')
+    op.drop_index(op.f('ix_admins_username'), table_name='admins')
+    op.drop_index(op.f('ix_admins_id'), table_name='admins')
+    op.drop_table('admins')
+    # ### end Alembic commands ###

backend/app/models/base.py

@@ -1,25 +1,32 @@
-from sqlalchemy.ext.declarative import declarative_base
+from sqlalchemy.orm import declarative_base
-from sqlalchemy.ext.asyncio import create_async_engine, AsyncSession
-from sqlalchemy.orm import sessionmaker
-from app.config import get_settings
-
-settings = get_settings()
-
-# Convert postgresql:// to postgresql+asyncpg://
-database_url = settings.database_url.replace(
-    "postgresql://", "postgresql+asyncpg://"
-)
-
-engine = create_async_engine(database_url, echo=True)
-
-AsyncSessionLocal = sessionmaker(
-    engine, class_=AsyncSession, expire_on_commit=False
-)
 
 Base = declarative_base()
 
 
+def get_async_engine():
+    """Create async engine on demand to avoid import-time config issues."""
+    from sqlalchemy.ext.asyncio import create_async_engine
+    from app.config import get_settings
+
+    settings = get_settings()
+    database_url = settings.database_url.replace(
+        "postgresql://", "postgresql+asyncpg://"
+    )
+    return create_async_engine(database_url, echo=True)
+
+
+def get_async_session():
+    """Create async session factory."""
+    from sqlalchemy.ext.asyncio import AsyncSession
+    from sqlalchemy.orm import sessionmaker
+
+    engine = get_async_engine()
+    return sessionmaker(engine, class_=AsyncSession, expire_on_commit=False)
+
+
 async def get_db():
+    """Dependency for FastAPI routes."""
+    AsyncSessionLocal = get_async_session()
     async with AsyncSessionLocal() as session:
         try:
             yield session

backend/app/services/ai_generator.py

@@ -63,7 +63,7 @@ Responde SOLO con el JSON, sin texto adicional."""
 
         try:
             message = self.client.messages.create(
-                model="claude-3-5-sonnet-20241022",
+                model="claude-3-haiku-20240307",
                 max_tokens=2000,
                 messages=[
                     {"role": "user", "content": prompt}

backend/requirements.txt

@@ -32,6 +32,6 @@ python-dotenv==1.0.0
 apscheduler==3.10.4
 
 # Testing
-pytest==8.0.0
+pytest>=7.0.0,<8.0.0
 pytest-asyncio==0.23.4
 httpx==0.26.0