Added sanity check baseline made by claude.

Also changed the location to a panel in VIEW_3D instead of menu.

providers.py

@@ -0,0 +1,22 @@
+"""Hooks to production tracking (Libreflow / Kitsu).
+
+These functions are the single place where checks ask the outside world for
+expected values. Return None when the information is unavailable: the
+related checks are then skipped instead of failing.
+"""
+
+
+def get_shot_frame_range(ctx):
+    """Return the expected (frame_start, frame_end) of the shot, or None.
+
+    ``ctx`` is a ``core.CheckContext``: ``ctx.filepath``, ``ctx.filename_match``
+    (groups "sequence" and "shot" of config.FILENAME_PATTERNS["LAYOUT"]) and
+    ``ctx.scene`` help identify the shot.
+
+    TODO: query Libreflow or Kitsu (gazu), e.g.::
+
+        import gazu
+        shot = gazu.shot.get_shot_by_name(sequence, shot_name)
+        start = shot["data"]["frame_in"]; end = shot["data"]["frame_out"]
+    """
+    return None