Mirrors the read path added in 47277c7: updateSaveDataWithStruct now
flushes Zenny/GZenny/CP back to the blob for ZZ, using the same
`ok && off > 0 && off+size <= len(blob)` guard so unmapped modes remain
inert.
Tests lock down byte-level idempotence — the most important invariant
for save data. Parsing a live kirito ZZ blob and immediately writing
the struct back produces a byte-identical blob, so enabling these
fields cannot silently corrupt existing player saves on the next save
cycle. Additional coverage: round-trip through both paths, non-ZZ
modes never touch the blob bytes, and truncated blobs don't panic on
write.
Adds read-only parsing for three scalar fields in the ZZ character save
blob: zenny (0xB0), gzenny (0x1FF64) and caravan points (0x212E4). Also
registers an offset for current_equip (0x1F604); extraction deferred
until its length is reverse-engineered. Offsets sourced from
Chakratos/mhf-save-manager and validated against a live HR999 blob.
Scope is intentionally ZZ-only: mhf-save-manager's F5 and G1-G5.2 maps
are not validated against live data, and the dormant pPlaytime vs
item_pouch collision in those versions is not resolved yet. Non-ZZ
modes leave the new pointers unmapped, and the read path is guarded by
`ok && off > 0 && off+size <= len(blob)` so unverified versions cannot
accidentally read from the blob.
Tests cover positive-path roundtrip (including live kirito blob),
regression guards for existing fields, non-ZZ isolation, new-character
skip, and bounds safety against truncated blobs.
