libScePlayGo technical debt

libScePlayGo - the chunk set comes from playgo-chunkdefs.xml (every listed chunk plus chunks 0 through the default chunk), otherwise from sce_sys/playgo-chunk.dat, whose plgx header is read as holding the chunk count as a 16-bit value at offset 0x0A and ids 0 to count - 1 are taken as valid. The field was identified on four dumps, where exactly that many 0x20-byte entries follow from offset 0x100 (RIDE 4 PPSA01599: 35, Persona 5 Royal PPSA05110: 25, LEGO Horizon Adventures PPSA14632 and Kena PPSA01802: 1); the rest of the format is not decoded and ids are assumed to be contiguous. Every listed chunk is reported as installed (LOCAL_FAST). Without either file, a package with sce_sys/playgo-scenario.json (PPSA01748, whose dump lists no chunks) accepts every chunk id as installed while scePlayGoGetChunkId lists only chunk 0, and a package with no playgo-* file in sce_sys (PPSA03001, PPSA03490 and PPSA01285 here) accepts only chunk 0 and returns SCE_PLAYGO_ERROR_BAD_CHUNK_ID for any other id; a sce_sys that holds other playgo-* files (playgo-ficm.dat, playgo-hash-table.dat) without playgo-chunk.dat or playgo-scenario.json, or a playgo-chunk.dat without a plgx header and a nonzero count, throws naming the file, because no such dump is known; the two answers above are unverified on a console, as is the console's answer for an id outside a package's chunk table.