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

src/baudolo/restore/paths.py

@@ -0,0 +1,29 @@
+from __future__ import annotations
+
+import os
+from dataclasses import dataclass
+
+
+@dataclass(frozen=True)
+class BackupPaths:
+    volume_name: str
+    backup_hash: str
+    version: str
+    repo_name: str
+    backups_dir: str = "/Backups"
+
+    def root(self) -> str:
+        # Always build an absolute path under backups_dir
+        return os.path.join(
+            self.backups_dir,
+            self.backup_hash,
+            self.repo_name,
+            self.version,
+            self.volume_name,
+        )
+
+    def files_dir(self) -> str:
+        return os.path.join(self.root(), "files")
+
+    def sql_file(self, db_name: str) -> str:
+        return os.path.join(self.root(), "sql", f"{db_name}.backup.sql")