feat: re-profile 22 emulators, refactor validation to common.py

batch re-profiled nekop2 through pokemini. mupen64plus renamed to
mupen64plus_next. new profiles: nes, mupen64plus_next.
validation functions (_build_validation_index, check_file_validation)
consolidated in common.py — single source of truth for verify.py
and generate_pack.py. pipeline 100% consistent on all 6 platforms.

emulators/onsyuri.yml

@@ -1,7 +1,9 @@
 emulator: ONScripter Yuri
 type: game
-source: "https://github.com/libretro/libretro-onsyuri"
-profiled_date: "2026-03-18"
+core_classification: game_engine
+source: "https://github.com/YuriSizuku/OnscripterYuri"
+upstream: "https://github.com/YuriSizuku/OnscripterYuri"
+profiled_date: "2026-03-24"
 core_version: "0.7.4+2"
 display_name: "ONScripter Yuri"
 cores:
@@ -10,13 +12,10 @@ systems:
   - onscripter
 
 notes: |
-  ONScripter Yuri is a fork of ONScripter optimized for the libretro
-  environment. Like the original ONScripter, it is a clone of the
-  NScripter visual novel engine and runs .txt, .dat, and .ons script
-  files.
-
-  No BIOS or system files required. Game content (scripts, graphics,
-  audio, fonts) is loaded from the game directory. Each game ships its
-  own default.ttf font file.
+  Clone of the NScripter visual novel engine, forked from ONScripter-Jh.
+  The libretro port lives in the upstream repo (src/onsyuri_libretro/).
+  No system files required. Game scripts (0.txt, nscript.dat, etc.),
+  fonts (default.ttf), and assets are loaded from the game directory.
+  The core does not use RetroArch's system directory.
 
 files: []