feat: migrate receiptwitness to standalone repo with inlined common

Extract receiptwitness/ from the monorepo into cartsnitch/receiptwitness.
Inline the consumed modules from cartsnitch-common so there is no
cross-repo dependency.

- Add src/receiptwitness/shared/ with inlined models, schemas, constants, database
- Update all imports from cartsnitch_common to receiptwitness.shared
- Remove cartsnitch-common dependency from pyproject.toml
- Copy and update Alembic config (alembic.ini, alembic/)
- Update Dockerfile for standalone build context, add migration CMD
- Add CI workflow with lint, test, build, grype scan, deploy-dev, deploy-uat
- Add .grype.yaml

Co-Authored-By: Paperclip <noreply@paperclip.ing>

alembic/env.py

@@ -0,0 +1,51 @@
+"""Alembic environment configuration for CartSnitch."""
+
+import os
+from logging.config import fileConfig
+
+from sqlalchemy import engine_from_config, pool
+
+from alembic import context
+from receiptwitness.shared.models.base import Base
+
+config = context.config
+if config.config_file_name is not None:
+    fileConfig(config.config_file_name)
+
+db_url = os.environ.get("CARTSNITCH_DATABASE_URL_SYNC")
+if db_url:
+    config.set_main_option("sqlalchemy.url", db_url.replace("%", "%%"))
+
+target_metadata = Base.metadata
+
+
+def run_migrations_offline() -> None:
+    """Run migrations in 'offline' mode."""
+    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:
+    """Run migrations in 'online' mode."""
+    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()

alembic/script.py.mako

@@ -0,0 +1,25 @@
+"""${message}
+
+Revision ID: ${up_revision}
+Revises: ${down_revision | comma,n}
+Create Date: ${create_date}
+"""
+
+from typing import Sequence, Union
+
+import sqlalchemy as sa
+from alembic import op
+${imports if imports else ""}
+
+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"}

alembic/versions/001_add_email_inbound_token.py

@@ -0,0 +1,37 @@
+"""Add email_inbound_token to users.
+
+Revision ID: 001_add_email_inbound_token
+Revises:
+Create Date: 2026-04-02
+"""
+
+from collections.abc import Sequence
+
+import sqlalchemy as sa
+
+from alembic import op
+
+revision: str = "001_add_email_inbound_token"
+down_revision: str | None = None
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def upgrade() -> None:
+    op.add_column("users", sa.Column("email_inbound_token", sa.String(22), nullable=True))
+    op.create_unique_constraint("uq_users_email_inbound_token", "users", ["email_inbound_token"])
+
+    # Backfill existing users with generated tokens (PostgreSQL)
+    op.execute(
+        "UPDATE users SET email_inbound_token = "
+        "substring(replace(gen_random_uuid()::text, '-', ''), 1, 22) "
+        "WHERE email_inbound_token IS NULL"
+    )
+
+    # Alter to non-nullable
+    op.alter_column("users", "email_inbound_token", nullable=False)
+
+
+def downgrade() -> None:
+    op.drop_constraint("uq_users_email_inbound_token", "users", type_="unique")
+    op.drop_column("users", "email_inbound_token")