chore: declare scripts as a package

The modules are run directly, run with -m, and imported by the tests and
the type checker. Only the first form puts this directory on the path, so
the package marker carries the bootstrap the other two need; without it
the first sibling import fails. Three tests hold the three forms open.

scripts/__init__.py

@@ -0,0 +1,19 @@
+"""Build and verification tooling for the collection.
+
+These modules are run as scripts (``python scripts/verify.py``), as modules
+(``python -m scripts.scraper.libretro_scraper``), and imported as a package by
+the tests and the type checker. The first form puts this directory on the path
+itself; the other two do not, so importing the package adds it. Without that,
+``import scripts.common`` fails on the first sibling import it reaches, and
+every absolute import between siblings would have to be rewritten to be
+relative -a change that would break running a script directly.
+"""
+
+from __future__ import annotations
+
+import os
+import sys
+
+_HERE = os.path.dirname(os.path.abspath(__file__))
+if _HERE not in sys.path:
+    sys.path.insert(0, _HERE)