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/helpers.py

@@ -7,6 +7,14 @@ import time
 import uuid
 from pathlib import Path
 
+# SPOT for the database images and their in-container data dirs the e2e
+# suite runs against. postgres:alpine tracks latest (18+), which mounts at
+# /var/lib/postgresql (not /var/lib/postgresql/data); bump here only.
+POSTGRES_IMAGE = "postgres:alpine"
+POSTGRES_DATA_DIR = "/var/lib/postgresql"
+MARIADB_IMAGE = "mariadb:latest"
+MARIADB_DATA_DIR = "/var/lib/mysql"
+
 
 def run(
     cmd: list[str],
@@ -172,7 +180,7 @@ def backup_run(
         "baudolo",
         "--compose-dir",
         compose_dir,
-        "--docker-compose-hard-restart-required",
+        "--hard-restart-projects",
         "mailu",
         "--repo-name",
         repo_name,