feat(backup)!: mandatory repo-name and databases-csv, --only-files, --only-sql

Two defaults could not be right. --repo-name fell back to the literal 'backup-docker-to-local' while its help promised the git repo folder name, which nothing ever derived. --databases-csv pointed inside the installed package directory, where credentials must not live; when it applied, load_databases_df read a missing file as empty and the run finished without a single dump and without an error. Both are required now, --repo-name in the restore CLI too. The file itself may still be absent - babadcb's tolerance is untouched, only the path must be named.

--everything is withdrawn. Its one effect was to ignore --images-no-stop-required, which is what leaving that list empty already does, and its branch was the default path minus the requires_stop check. No caller, no test, and help and README described it differently.

--dump-only-sql becomes --only-sql, and --only-files joins it as the opposite half: no dumps at all, every volume as files. They form a mutually exclusive group. A host that only copies files has no business holding database passwords, so --databases-csv is not required there and is never read.

The smallest valid argv turned out to be written four times across the test tree; it now lives once. Withdrawn flags are listed in one place and proven to exit 2.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/baudolo/backup/cli.py

@@ -1,13 +1,9 @@
 from __future__ import annotations
 
 import argparse
-import os
 
 
 def parse_args() -> argparse.Namespace:
-    dirname = os.path.dirname(__file__)
-    default_databases_csv = os.path.join(dirname, "databases.csv")
-
     p = argparse.ArgumentParser(description="Backup Docker volumes.")
 
     p.add_argument(
@@ -25,13 +21,12 @@ def parse_args() -> argparse.Namespace:
 
     p.add_argument(
         "--repo-name",
-        default="backup-docker-to-local",
-        help="Backup repo folder name under <backups-dir>/<machine-id>/ (default: git repo folder name)",
+        required=True,
+        help="Backup repo folder name under <backups-dir>/<machine-id>/",
     )
     p.add_argument(
         "--databases-csv",
-        default=default_databases_csv,
-        help=f"Path to databases.csv (default: {default_databases_csv})",
+        help="Path to databases.csv; required unless --only-files is given",
     )
     p.add_argument(
         "--backups-dir",
@@ -75,19 +70,15 @@ def parse_args() -> argparse.Namespace:
         help="Exact volume names that are never backed up, whatever containers use them. For derived trees a restore cannot reproduce, above all a nested docker data root",
     )
 
-    p.add_argument(
-        "--everything",
-        action="store_true",
-        help="Force file backup for all volumes and also execute database dumps (like old script)",
-    )
     p.add_argument(
         "--shutdown",
         action="store_true",
         help="Do not restart containers after backup",
     )
 
-    p.add_argument(
-        "--dump-only-sql",
+    scope = p.add_mutually_exclusive_group()
+    scope.add_argument(
+        "--only-sql",
         action="store_true",
         help=(
             "Create database dumps only for DB volumes. "
@@ -96,7 +87,19 @@ def parse_args() -> argparse.Namespace:
             "If a DB dump cannot be produced, baudolo falls back to a file backup."
         ),
     )
+    scope.add_argument(
+        "--only-files",
+        action="store_true",
+        help=(
+            "Take no database dumps at all and back up every volume as files. "
+            "For hosts that hold no database credentials. A database's files "
+            "are only consistent if its containers are stopped for the second "
+            "pass, so keep its image off --images-no-stop-required."
+        ),
+    )
     args = p.parse_args()
+    if not args.only_files and not args.databases_csv:
+        p.error("--databases-csv is required unless --only-files is given")
     if bool(args.snapshot) != bool(args.snapshot_subject):
         p.error("--snapshot and --snapshot-subject must be given together")
     if args.snapshot and args.shutdown: