Phase 1: auth, room CRUD, WebSocket chat, PWA frontend

Invite-only FastAPI + SQLAlchemy(async) + Postgres backend (session-cookie
auth via CLI-provisioned accounts, open-room CRUD, single-instance /ws/chat)
and a React + Vite PWA frontend (login, room list, chat view). Backend tests
pass against a local Postgres DB. See README.md and backend/README.md for
setup, and ARCHITECTURE.md for the full phased design.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

backend/alembic/README

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+Generic single-database configuration with an async dbapi.

backend/alembic/env.py

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+import asyncio
+import os
+from logging.config import fileConfig
+
+from sqlalchemy import pool
+from sqlalchemy.engine import Connection
+from sqlalchemy.ext.asyncio import async_engine_from_config
+
+from alembic import context
+from app.models import Base
+
+# this is the Alembic Config object, which provides
+# access to the values within the .ini file in use.
+config = context.config
+
+# Interpret the config file for Python logging.
+# This line sets up loggers basically.
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+# add your model's MetaData object here
+# for 'autogenerate' support
+target_metadata = Base.metadata
+
+# Allow the DB URL to come from the environment (matches app/config.py),
+# falling back to alembic.ini's sqlalchemy.url for local dev convenience.
+db_url = os.environ.get("DATABASE_URL")
+if db_url:
+    config.set_main_option("sqlalchemy.url", db_url)
+
+# other values from the config, defined by the needs of env.py,
+# can be acquired:
+# my_important_option = config.get_main_option("my_important_option")
+# ... etc.
+
+
+def run_migrations_offline() -> None:
+    """Run migrations in 'offline' mode.
+
+    This configures the context with just a URL
+    and not an Engine, though an Engine is acceptable
+    here as well.  By skipping the Engine creation
+    we don't even need a DBAPI to be available.
+
+    Calls to context.execute() here emit the given string to the
+    script output.
+
+    """
+    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 do_run_migrations(connection: Connection) -> None:
+    context.configure(connection=connection, target_metadata=target_metadata)
+
+    with context.begin_transaction():
+        context.run_migrations()
+
+
+async def run_async_migrations() -> None:
+    """In this scenario we need to create an Engine
+    and associate a connection with the context.
+
+    """
+
+    connectable = async_engine_from_config(
+        config.get_section(config.config_ini_section, {}),
+        prefix="sqlalchemy.",
+        poolclass=pool.NullPool,
+    )
+
+    async with connectable.connect() as connection:
+        await connection.run_sync(do_run_migrations)
+
+    await connectable.dispose()
+
+
+def run_migrations_online() -> None:
+    """Run migrations in 'online' mode."""
+
+    asyncio.run(run_async_migrations())
+
+
+if context.is_offline_mode():
+    run_migrations_offline()
+else:
+    run_migrations_online()

backend/alembic/script.py.mako

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+"""${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, Sequence[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:
+    """Upgrade schema."""
+    ${upgrades if upgrades else "pass"}
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    ${downgrades if downgrades else "pass"}

backend/alembic/versions/c7981d17890c_initial_schema.py

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+"""initial schema
+
+Revision ID: c7981d17890c
+Revises: 
+Create Date: 2026-08-13 19:40:11.425029
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision: str = 'c7981d17890c'
+down_revision: Union[str, Sequence[str], None] = None
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Upgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.create_table('users',
+    sa.Column('id', sa.Uuid(), nullable=False),
+    sa.Column('username', sa.String(length=50), nullable=False),
+    sa.Column('email', sa.String(length=255), nullable=False),
+    sa.Column('password_hash', sa.String(length=255), nullable=False),
+    sa.Column('is_bot', sa.Boolean(), nullable=False),
+    sa.Column('is_site_admin', sa.Boolean(), nullable=False),
+    sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('now()'), nullable=False),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_users_email'), 'users', ['email'], unique=True)
+    op.create_index(op.f('ix_users_username'), 'users', ['username'], unique=True)
+    op.create_table('rooms',
+    sa.Column('id', sa.Uuid(), nullable=False),
+    sa.Column('name', sa.String(length=100), nullable=False),
+    sa.Column('description', sa.Text(), nullable=True),
+    sa.Column('is_private', sa.Boolean(), nullable=False),
+    sa.Column('owner_id', sa.Uuid(), nullable=False),
+    sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('now()'), nullable=False),
+    sa.ForeignKeyConstraint(['owner_id'], ['users.id'], ),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_rooms_name'), 'rooms', ['name'], unique=True)
+    op.create_table('messages',
+    sa.Column('id', sa.Uuid(), nullable=False),
+    sa.Column('room_id', sa.Uuid(), nullable=False),
+    sa.Column('user_id', sa.Uuid(), nullable=False),
+    sa.Column('content', sa.Text(), nullable=False),
+    sa.Column('created_at', sa.DateTime(timezone=True), server_default=sa.text('now()'), nullable=False),
+    sa.Column('edited_at', sa.DateTime(timezone=True), nullable=True),
+    sa.Column('deleted_at', sa.DateTime(timezone=True), nullable=True),
+    sa.ForeignKeyConstraint(['room_id'], ['rooms.id'], ),
+    sa.ForeignKeyConstraint(['user_id'], ['users.id'], ),
+    sa.PrimaryKeyConstraint('id')
+    )
+    op.create_index(op.f('ix_messages_created_at'), 'messages', ['created_at'], unique=False)
+    op.create_index(op.f('ix_messages_room_id'), 'messages', ['room_id'], unique=False)
+    op.create_table('room_memberships',
+    sa.Column('room_id', sa.Uuid(), nullable=False),
+    sa.Column('user_id', sa.Uuid(), nullable=False),
+    sa.Column('role', sa.Enum('owner', 'admin', 'member', name='room_role'), nullable=False),
+    sa.Column('joined_at', sa.DateTime(timezone=True), server_default=sa.text('now()'), nullable=False),
+    sa.ForeignKeyConstraint(['room_id'], ['rooms.id'], ),
+    sa.ForeignKeyConstraint(['user_id'], ['users.id'], ),
+    sa.PrimaryKeyConstraint('room_id', 'user_id')
+    )
+    # ### end Alembic commands ###
+
+
+def downgrade() -> None:
+    """Downgrade schema."""
+    # ### commands auto generated by Alembic - please adjust! ###
+    op.drop_table('room_memberships')
+    op.drop_index(op.f('ix_messages_room_id'), table_name='messages')
+    op.drop_index(op.f('ix_messages_created_at'), table_name='messages')
+    op.drop_table('messages')
+    op.drop_index(op.f('ix_rooms_name'), table_name='rooms')
+    op.drop_table('rooms')
+    op.drop_index(op.f('ix_users_username'), table_name='users')
+    op.drop_index(op.f('ix_users_email'), table_name='users')
+    op.drop_table('users')
+    # ### end Alembic commands ###