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

tests/e2e/test_e2e_files_full.py

@@ -0,0 +1,84 @@
+import unittest
+from pathlib import Path
+
+from .helpers import (
+    backup_run,
+    backup_path,
+    cleanup_docker,
+    create_minimal_compose_dir,
+    ensure_empty_dir,
+    latest_version_dir,
+    require_docker,
+    unique,
+    write_databases_csv,
+    run,
+)
+
+
+class TestE2EFilesFull(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls) -> None:
+        require_docker()
+        cls.prefix = unique("baudolo-e2e-files-full")
+        cls.backups_dir = f"/tmp/{cls.prefix}/Backups"
+        ensure_empty_dir(cls.backups_dir)
+
+        cls.compose_dir = create_minimal_compose_dir(f"/tmp/{cls.prefix}")
+        cls.repo_name = cls.prefix
+
+        cls.volume_src = f"{cls.prefix}-vol-src"
+        cls.volume_dst = f"{cls.prefix}-vol-dst"
+        cls.containers = []
+        cls.volumes = [cls.volume_src, cls.volume_dst]
+
+        # create source volume with a file
+        run(["docker", "volume", "create", cls.volume_src])
+        run([
+            "docker", "run", "--rm",
+            "-v", f"{cls.volume_src}:/data",
+            "alpine:3.20",
+            "sh", "-lc", "mkdir -p /data && echo 'hello' > /data/hello.txt",
+        ])
+
+        # databases.csv (unused, but required by CLI)
+        cls.databases_csv = f"/tmp/{cls.prefix}/databases.csv"
+        write_databases_csv(cls.databases_csv, [])
+
+        # Run backup (files should be copied)
+        backup_run(
+            backups_dir=cls.backups_dir,
+            repo_name=cls.repo_name,
+            compose_dir=cls.compose_dir,
+            databases_csv=cls.databases_csv,
+            database_containers=["dummy-db"],
+            images_no_stop_required=["alpine", "postgres", "mariadb", "mysql"],
+        )
+
+        cls.hash, cls.version = latest_version_dir(cls.backups_dir, cls.repo_name)
+
+    @classmethod
+    def tearDownClass(cls) -> None:
+        cleanup_docker(containers=cls.containers, volumes=cls.volumes)
+
+    def test_files_backup_exists(self) -> None:
+        p = backup_path(self.backups_dir, self.repo_name, self.version, self.volume_src) / "files" / "hello.txt"
+        self.assertTrue(p.is_file(), f"Expected backed up file at: {p}")
+
+    def test_restore_files_into_new_volume(self) -> None:
+        # restore files into dst volume
+        run([
+            "baudolo-restore", "files",
+            self.volume_dst, self.hash, self.version,
+            "--backups-dir", self.backups_dir,
+            "--repo-name", self.repo_name,
+            "--rsync-image", "ghcr.io/kevinveenbirkenbach/alpine-rsync",
+        ])
+
+        # verify restored file exists in dst volume
+        p = run([
+            "docker", "run", "--rm",
+            "-v", f"{self.volume_dst}:/data",
+            "alpine:3.20",
+            "sh", "-lc", "cat /data/hello.txt",
+        ])
+        self.assertEqual((p.stdout or "").strip(), "hello")