refactor: migrate to src/ package + add DinD-based E2E runner with debug artifacts

- Replace legacy standalone scripts with a proper src-layout Python package
  (baudolo backup/restore/configure entrypoints via pyproject.toml)
- Remove old scripts/files (backup-docker-to-local.py, recover-docker-from-local.sh,
  databases.csv.tpl, Todo.md)
- Add Dockerfile to build the project image for local/E2E usage
- Update Makefile: build image and run E2E via external runner script
- Add scripts/test-e2e.sh:
  - start DinD + dedicated network
  - recreate DinD data volume (and shared /tmp volume)
  - pre-pull helper images (alpine-rsync, alpine)
  - load local baudolo:local image into DinD
  - run unittest E2E suite inside DinD and abort on first failure
  - on failure: dump host+DinD diagnostics and archive shared /tmp into artifacts/
- Add artifacts/ debug outputs produced by failing E2E runs (logs, events, tmp archive)

https://chatgpt.com/share/694ec23f-0794-800f-9a59-8365bc80f435

Makefile

@@ -1,12 +1,41 @@
-.PHONY: test
+.PHONY: install build test-e2e
 
-test:
-	python -m unittest discover -s tests/unit -p "test_*.py"
+# Default python if no venv is active
+PY_DEFAULT ?= python3
+
+IMAGE_NAME ?= baudolo
+IMAGE_TAG  ?= local
+IMAGE      := $(IMAGE_NAME):$(IMAGE_TAG)
 
 install:
-	@echo ">> Installation instructions:"
-	@echo "   This software can be installed with pkgmgr under the alias 'baudolo':"
-	@echo "     pkgmgr install baudolo"
-	@echo ""
-	@echo "   📦 pkgmgr project page:"
-	@echo "     https://github.com/kevinveenbirkenbach/package-manager"
+	@set -eu; \
+	PY="$(PY_DEFAULT)"; \
+	if [ -n "$${VIRTUAL_ENV:-}" ] && [ -x "$${VIRTUAL_ENV}/bin/python" ]; then \
+		PY="$${VIRTUAL_ENV}/bin/python"; \
+	fi; \
+	echo ">>> Using python: $$PY"; \
+	"$$PY" -m pip install --upgrade pip; \
+	"$$PY" -m pip install -e .; \
+	command -v baudolo >/dev/null 2>&1 || { \
+		echo "ERROR: baudolo not found on PATH after install"; \
+		exit 2; \
+	}; \
+	baudolo --help >/dev/null 2>&1 || true
+
+# ------------------------------------------------------------
+# Build the baudolo Docker image
+# ------------------------------------------------------------
+build:
+	@echo ">> Building Docker image $(IMAGE)"
+	docker build -t $(IMAGE) .
+
+# ------------------------------------------------------------
+# Run E2E tests inside the container (Docker socket required)
+# ------------------------------------------------------------
+# E2E via isolated Docker-in-Docker (DinD)
+# - depends on local image build
+# - starts a DinD daemon container on a dedicated network
+# - loads the freshly built image into DinD
+# - runs the unittest suite inside a container that talks to DinD via DOCKER_HOST
+test-e2e: build
+	@bash scripts/test-e2e.sh