Update .dockerignore, alembic revision, and entrypoint script for consistency and reliability

- Expanded `.dockerignore` to exclude Python and packaging-related artifacts for cleaner Docker builds.
- Updated Alembic `down_revision` in migration script to reflect correct dependency chain.
- Modified entrypoint script to use `uv` with `--no-project` flag, preventing permission issues in bind-mounted volumes.

README.md

@@ -1,6 +1,6 @@
 # PragmaStack
 
-<div align="center">
+<div style="text-align: center">
   <img src="frontend/public/logo.svg" alt="PragmaStack Logo" width="200" />
   <br />
 </div>