feat: complete 294/294 libretro core profiling

Final batch: stonesoup, vitaquake3+vitavoyager, uw8, uxn, wasm4,
tempgba, retro8, moonlight, ffmpeg, imageviewer, mpv, remotejoy,
puzzlescript, lutro, mojozork, simcp (SAM Coupe, ROM built-in),
romcleaner, redbook, onsyuri, mcsoftserve, x64sdl (VICE alias)

204 total emulator/core profiles covering ALL 294 libretro cores.
Every core analyzed from source code. Complete museum documentation.

emulators/x64sdl.yml

@@ -0,0 +1,17 @@
+emulator: x64sdl
+type: libretro
+source: "https://github.com/libretro/vice-libretro"
+cores:
+  - vice_x64
+systems:
+  - commodore-c64
+
+notes: |
+  Alias for the VICE x64 core. x64sdl is an alternate build name
+  referencing the SDL-based VICE x64 Commodore 64 emulator. In the
+  libretro ecosystem this maps to the same vice_x64 core binary.
+
+  See vice.yml for full ROM and BIOS details. All standard ROMs are
+  embedded in the core binary.
+
+files: []