Add readers for Project Sylpheed's on-disc data format so the
reimplementation can load exact ship/weapon constants straight from
the game files.
- pak.rs: PakArchive — parse the IPFB `.pak` index + concatenated
`.pNN` segments, binary-search the TOC by name-hash, and transparently
inflate the per-entry "Z1" (zlib) container. Adds flate2.
- idxd.rs: IdxdObject — parse the IDXD reflective object serialization.
The string pool stores properties value-before-key with defaulted
fields omitted; typed getters (get_f32/get_i64/get_str/get_bool) read
explicit values reliably, get_raw exposes identifier fields, and
resolved_fields() enumerates every explicit (key,value). Defaulted
fields correctly return None rather than a neighbouring key.
- sylpheed-cli: `pak list` (inventory entries + identity) and
`pak dump <hash>` (full stat sheet for one object).
Verified against the real disc (auto-skipped without it): DeltaSaber
craft (HP=1000, Acceleration=600, velocity curve 100/700/1200, Turn=100,
RadarRange=500000) and the DSaber missile (LoadingCount=144, Interval=3.00,
Mass=0.77). 10 unit + 3 integration tests pass.
Not yet decoded: defaulted fields (many ratios, the *Count family) whose
values come from schema defaults or the hash-keyed binary node region.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
