feat(backup)!: exact --images-* matching and --hard-restart-projects

Match --images-no-stop-required and --images-no-backup-required against
the container's exact .Config.Image instead of a substring, so callers
pass full repo:tag references (registry prefix included) and near-miss
image names no longer flip the stop/skip decision. Rename the opt-in
--hard-compose-restart flag to --hard-restart-projects.

The e2e suite pins a SPOT for the DB images and in-container data dirs
(postgres:alpine at /var/lib/postgresql, mariadb:latest at
/var/lib/mysql) and passes exact image refs to the --images-* flags.

BREAKING CHANGE: --images-* now require exact image references, not
substrings; --hard-compose-restart is renamed to --hard-restart-projects.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/e2e/test_e2e_mariadb_anonymous_preemption.py

@@ -30,6 +30,8 @@ import pandas
 from baudolo.backup import db as db_mod
 
 from .helpers import (
+    MARIADB_IMAGE,
+    MARIADB_DATA_DIR,
     cleanup_docker,
     require_docker,
     run,
@@ -69,8 +71,8 @@ class TestE2EMariaDBAnonymousPreemption(unittest.TestCase):
                 "-e",
                 f"MARIADB_ROOT_PASSWORD={cls.root_password}",
                 "-v",
-                f"{cls.db_volume}:/var/lib/mysql",
-                "mariadb:12.2",
+                f"{cls.db_volume}:{MARIADB_DATA_DIR}",
+                MARIADB_IMAGE,
             ]
         )