feat: add 10 emulator profiles (119-series batch 2)

freeintv_ts_overlay (same BIOS as FreeIntv), bnes (NES, no BIOS),
clownmdemu (Mega Drive, open-source MCD boot ROM embedded),
m2000 (Philips P2000T, all embedded), mesen (NES, FDS + StudyBox BIOS),
race (NGP, HLE with disabled BIOS loader), vemulator (VMU, HLE only),
gw (Game & Watch, Lua simulator), pd777 (Cassette Vision, no BIOS),
play (PS2, full HLE, LoadBIOS commented out)

115 total profiles.

emulators/vemulator.yml

@@ -0,0 +1,72 @@
+emulator: VeMUlator
+type: libretro
+source: "https://github.com/libretro/vemulator-libretro"
+cores:
+  - vemulator
+systems:
+  - sega-vmu
+
+notes: |
+  VeMUlator is a Sega Dreamcast Visual Memory Unit (VMU/VMS) emulator ported
+  from Android (Java) to C++ for libretro. It emulates the Sanyo LC8670
+  "Potato" CPU, 128 KB flash memory, 48x32 monochrome LCD, piezo buzzer,
+  and basic timer subsystems.
+
+  No BIOS files are required. The core uses High Level Emulation (HLE) to
+  bypass the VMU firmware entirely:
+
+  - At startup, startCPU() checks the BIOSExists flag (vmu.cpp:195). When
+    false (always, in the libretro port), it calls initializeHLE() which
+    sets up SFR registers (SP=0x7F, PSW=0x02, IE=0x80, MCR=0x08, P7=0x02,
+    OCR=0xA3, BTCR=0x41) and system RAM variables directly (vmu.cpp:206-222).
+
+  - A loadBIOS() function exists in the VMU class (vmu.cpp:82-137) and can
+    handle both encrypted (XOR 0x37, 4-byte header stripped) and unencrypted
+    BIOS images (first byte must be 0x2A = JMPF opcode). Maximum accepted
+    size is 0xF004 (61444) bytes, loaded into 0xF000 (61440) bytes of ROM.
+    However, this function is never called by the libretro frontend code.
+    retro_load_game() in main.cpp only loads game flash data, with no BIOS
+    path resolution or RETRO_ENVIRONMENT_GET_SYSTEM_DIRECTORY call.
+
+  - The README lists "BIOS support" as a planned future feature.
+
+  The .info file declares no firmware entries (firmware_count absent).
+  Supported ROM formats: VMS (.vms), DCI (.dci), raw flash dump (.bin).
+  The core option "enable_flash_write" allows persistent saves for .bin files.
+
+files: []
+
+platform_details:
+  hle_implementation:
+    source_ref: "vmu.cpp:195-222"
+    sfr_init:
+      SP: "0x7F"
+      PSW: "0x02"
+      IE: "0x80"
+      MCR: "0x08"
+      P7: "0x02"
+      OCR: "0xA3"
+      BTCR: "0x41"
+    ram_init:
+      - "0x31 = 0xFF (battery level)"
+      - "0x6E = 0xFF"
+      - "P3 = 0xFF (no buttons pressed)"
+      - "BCD date/time at 0x10-0x16, raw at 0x17-0x1D"
+    notes: |
+      HLE skips the BIOS boot sequence and jumps directly into the loaded
+      game. System clock, date, and button state are initialized in RAM.
+      The EXT register is set to 1 to signal HLE mode to the CPU
+      (vmu.cpp:198-199). Games that depend on BIOS-initialized state
+      beyond what HLE provides may not work correctly.
+
+  unused_bios_loader:
+    source_ref: "vmu.cpp:82-137"
+    max_file_size: 61444
+    rom_load_size: 61440
+    encryption: "XOR 0x37 after stripping 4-byte header"
+    detection: "first byte 0x2A (JMPF) = unencrypted, otherwise encrypted"
+    notes: |
+      The loadBIOS() method is fully implemented but unreachable from the
+      libretro interface. No system directory query, no BIOS path construction,
+      and no call site exists in main.cpp. A future update could wire this up
+      to support real VMU firmware boot (file manager, clock, mini-games menu).