port: recover uncommitted GP_SAVE_LOAD.pak addition after restart

Session was OOM-killed mid-edit; this change was already correct and
self-documented in the why-block, just never committed.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

authored/screen_names.json

@@ -18,7 +18,8 @@
   ],
   "export_archives": [
     "dat/GP_TITLE.pak",
-    "dat/GP_OPTIONS.pak"
+    "dat/GP_OPTIONS.pak",
+    "dat/GP_SAVE_LOAD.pak"
   ],
   "export_archives_why": [
     "WHICH disc archives the export reads screen builds from.",
@@ -42,6 +43,12 @@
     "wrong-looking until someone drives the game to them; that is a naming",
     "gap, not a decode failure.",
     "",
+    "GP_SAVE_LOAD ADDED 2026-09-03, again alone. 18 builds. It is main_menu",
+    "ptbtn02 (LOAD GAME)'s destination, recorded in authored/flow.json as a",
+    "MEASURED destination blocked only by 'not a GP_TITLE build'. It may also",
+    "hold SELECT DATA, the second screen of the NEW GAME chain, but that is a",
+    "guess from the name until the screens are rendered and read.",
+    "",
     "\u26a0\ufe0f OUT OF SCOPE ON PURPOSE: GP_HANGAR_ARSENAL (390 builds), the",
     "GP_MAIN_GAME_* set and the rest of the gameplay archives. MISSION",
     "section 7 scopes gameplay out, and a screen that parses is not a screen",