Fix FBNeo Pages romset launch - #13

Summary

• switch the GitHub Pages FBNeo compatibility romset from puzzledp to magdrop2 so the browser build can keep 4 MiB C1/C2 graphics ROMs
• launch the emulator with EJS_gameName=magdrop2 and magdrop2.zip while preserving project-named download copies
• pad/CRC-patch source chips into magdrop2 filenames and include the web BIOS entries in the launch zip for EmulatorJS/FBNeo
• update CI CRC checks and docs for the new Pages romset shape

Verification

• python3 -m py_compile tools/doomgeo_build.py
• python3 tools/doomgeo_build.py pages --rom build/rom/puzzledp.zip --bios build/rom/neogeo.zip --asm-rom build/asm-rom/puzzledp.zip --out build/pages-magdrop-test
• verified magdrop2.zip, doomgeo-aes.zip, ASM copies, and neogeo.zip sizes/CRCs
• served build/pages-magdrop-test locally and started EmulatorJS/FBNeo in Chrome; it requested magdrop2.zip and no longer showed the unknown/missing romset error