add alembic for migrations

[swelborn]

---

This is part 7 of 10 in a stack made with GitButler:

•  10  remove jwt/jwks from this #14
•  9  add idle timeout option #13
•  8  refactor into functional core/imperative shell #12
•  7  add alembic for migrations #11 👈
•  6  use a key to dedupe reqs #10
•  5  use anyio and fixup process handling #9
•  4  systemd + vault certs #8
•  3  feat: caller dictates the cache log path; drop RUN_DIR #7
•  2  minor model updates and configuration change since timeout was added #6
•  1  create ports locally to fastcache server #5

[Copilot]

Pull request overview

Adds Alembic-based schema migrations for the FastAPI service, replacing the prior “create tables on startup” approach and wiring migrations into local/dev workflows and the systemd unit.

Changes:

• Add Alembic (and dependencies) plus pyproject.toml configuration and hooks for formatting/checking generated revisions.
• Introduce an initial migration for the existing caches table and add an autogeneration helper script.
• Remove startup-time create_all() initialization and run alembic upgrade head via systemd ExecStartPre.

Reviewed changes

Copilot reviewed 9 out of 12 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
uv.lock	Locks Alembic and template dependencies (mako/markupsafe).
systemd/fastcache-api.service	Runs alembic upgrade head before starting the service.
src/fastcache_api/main.py	Removes DB initialization from app lifespan startup.
src/fastcache_api/db.py	Removes init_db() that previously ran Base.metadata.create_all().
src/fastcache_api/alembic/env.py	Adds Alembic environment script for running migrations.
src/fastcache_api/alembic/script.py.mako	Adds revision template for generated migrations.
src/fastcache_api/alembic/init.py	Marks Alembic directory as a package for script_location.
src/fastcache_api/alembic/versions/init.py	Marks versions directory as a package.
src/fastcache_api/alembic/versions/1d91b0606408_init.py	Adds initial schema migration creating caches table.
scripts/gen_migration.py	Adds helper to autogenerate migrations against a throwaway sqlite DB.
README.md	Documents migration workflow and systemd pre-start migration behavior.
pyproject.toml	Adds Alembic dependency and [tool.alembic] configuration + post-write hooks.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.