fix: run verify and generate_pack from any dir

Started outside the repository root, both ended on a FileNotFoundError
traceback: the database and the data registry name files from the root.
They now move to the root after reading the paths the caller typed, which
stay relative to where they were typed.

scripts/generate_pack.py

@@ -3160,6 +3160,12 @@ def _main(held: contextlib.ExitStack) -> None:
         help="Extract and verify pack integrity (path + hash)",
     )
     args = parser.parse_args()
+    from verify import work_from_repo_root
+
+    work_from_repo_root(
+        args, parser,
+        ["db", "platforms_dir", "bios_dir", "output_dir", "emulators_dir", "from_md5_file"],
+    )
     packresolve.set_offline(bool(args.offline))
     if args.platform:
         require_platform(args.platform, args.platforms_dir)

scripts/verify.py

@@ -109,6 +109,30 @@ DEFAULT_BIOS_DIR = "bios"
 # that pass no directory.
 _REPO_PLATFORMS = os.path.join(os.path.dirname(__file__), "..", "platforms")
 DEFAULT_EMULATORS_DIR = "emulators"
+REPO_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+
+
+def work_from_repo_root(
+    args: argparse.Namespace, parser: argparse.ArgumentParser, path_flags: list[str]
+) -> None:
+    """Run from the repository root, whichever directory the command started in.
+
+    database.json records every file from the root and the data registry
+    names its caches the same way, so a run from scripts/ ended on a
+    FileNotFoundError traceback. A path the caller typed is read from where
+    they typed it, a default from the root.
+    """
+    if os.path.realpath(os.getcwd()) == os.path.realpath(REPO_ROOT):
+        return
+    for flag in path_flags:
+        value = getattr(args, flag, None)
+        if value and value != parser.get_default(flag):
+            setattr(args, flag, os.path.abspath(value))
+    os.chdir(REPO_ROOT)
+    if getattr(args, "platform", None):
+        # Read before the move, the registry was not there to map
+        # "RetroArch" to its slug.
+        args.platform = platform_arg(args.platform)
 
 
 # Status model: aligned with Batocera BiosStatus (batocera-systems:967-969)
@@ -2367,6 +2391,7 @@ def _main(held: contextlib.ExitStack) -> None:
         "present with an unconfirmed hash is a warning, not a failure",
     )
     args = parser.parse_args()
+    work_from_repo_root(args, parser, ["db", "platforms_dir", "emulators_dir"])
     if args.platform:
         require_platform(args.platform, args.platforms_dir)