Rename the import package app to fluksio

A wheel whose top-level module is `app` collides with anything else in a
user's venv, so the package that is about to be published takes the name
it is published under. Only the Python package moves; the repo, the
Docker WORKDIR and the compose project keep theirs.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

scripts/generate-client.sh

@@ -4,7 +4,7 @@ set -e
 set -x
 
 cd backend
-uv run python -c "import app.main; import json; print(json.dumps(app.main.app.openapi()))" > ../openapi.json
+uv run python -c "import fluksio.main; import json; print(json.dumps(fluksio.main.app.openapi()))" > ../openapi.json
 cd ..
 mv openapi.json frontend/
 bun run --filter frontend generate-client