Fix 80020148 'game could not be started' on ARK-5: the base PBP's encrypted
~PSP loader fails to link on modern CFW. Use the bundled plain-ELF loader
(data/loader/DATA.PSP) as the DATA.PSP section instead, and write the 16-byte
NPDRM version key (data/loader/KEYS.BIN) alongside the EBOOT so CFW can
decrypt the STARTDAT PGD. Both assets are from iPoPS (MIT, attributed).
- load_data_psp: prefer the bundled ELF, fall back to the base ~PSP loader.
- load_keys_bin: return the bundled 16-byte key when present.
- convert: write KEYS.BIN next to the output EBOOT.
- README + data/loader/ATTRIBUTION.md: document the loader and its license.
- extract_startdat: locate STARTDAT at PSAR + p1 (the u32 at PSAR+0x0C)
instead of popstation's p1 + 0x50000 absolute offset, which only worked
for bases whose PSAR was aligned to 0x50000. Any PS1 classic can now be
used as a base.
- _warn_old_base: print a warning when the base PBP is a 3.xx-era classic,
since its POPS loader often fails to link on 6.60/6.61 CFW (error
80020148 'game could not be started').
- README: document the 6.60/6.61 base preference and DEFLATE compression.