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/db/mariadb.py

@@ -0,0 +1,83 @@
+from __future__ import annotations
+
+import os
+import sys
+
+from ..run import docker_exec, docker_exec_sh
+
+
+def _pick_client(container: str) -> str:
+    # Prefer mariadb, fallback to mysql (many images provide one or both).
+    script = r"""
+set -eu
+if command -v mariadb >/dev/null 2>&1; then echo mariadb; exit 0; fi
+if command -v mysql   >/dev/null 2>&1; then echo mysql;   exit 0; fi
+exit 42
+"""
+    try:
+        out = docker_exec_sh(container, script, capture=True).stdout.decode().strip()
+        if not out:
+            raise RuntimeError("empty client detection output")
+        return out
+    except Exception as e:
+        print("ERROR: neither 'mariadb' nor 'mysql' found in container.", file=sys.stderr)
+        raise e
+
+
+def restore_mariadb_sql(
+    *,
+    container: str,
+    db_name: str,
+    user: str,
+    password: str,
+    sql_path: str,
+    empty: bool,
+) -> None:
+    client = _pick_client(container)
+
+    if not os.path.isfile(sql_path):
+        raise FileNotFoundError(sql_path)
+
+    if empty:
+        # Close to old behavior: list tables, drop individually, then re-enable checks.
+        docker_exec(
+            container,
+            ["mysql", "-u", user, f"--password={password}", "-e", "SET FOREIGN_KEY_CHECKS=0;"],
+        )
+
+        result = docker_exec(
+            container,
+            [
+                "mysql",
+                "-u",
+                user,
+                f"--password={password}",
+                "-N",
+                "-e",
+                f"SELECT table_name FROM information_schema.tables WHERE table_schema = '{db_name}';",
+            ],
+            capture=True,
+        )
+        tables = result.stdout.decode().split()
+        for tbl in tables:
+            docker_exec(
+                container,
+                [
+                    "mysql",
+                    "-u",
+                    user,
+                    f"--password={password}",
+                    "-e",
+                    f"DROP TABLE IF EXISTS `{db_name}`.`{tbl}`;",
+                ],
+            )
+
+        docker_exec(
+            container,
+            ["mysql", "-u", user, f"--password={password}", "-e", "SET FOREIGN_KEY_CHECKS=1;"],
+        )
+
+    with open(sql_path, "rb") as f:
+        docker_exec(container, [client, "-u", user, f"--password={password}", db_name], stdin=f)
+
+    print(f"MariaDB/MySQL restore complete for db '{db_name}'.")