dev: switch to fully containerized Docker Compose workflow

- Replace tmux setup with a full Docker Compose development stack
- Update backend Dockerfile to use `cargo-chef` caching and `supervisord`
- Containerize frontend development server
- Update tests to run in isolated containers
- Remove legacy `papercrate.tmux`

backend/diesel.toml

@@ -1,6 +1,2 @@
-[print_schema]
-file = "src/schema.rs"
-custom_type_derives = ["diesel::query_builder::QueryId", "Clone"]
-
 [migrations_directory]
 dir = "migrations"