game_data: typed loaders for the combat / character / mission tables

Decode Project Sylpheed's IDXD data model into plain, cloneable structs
(from GP_MAIN_GAME_E.pak; the D/F/I/J/S paks are localized dups):

- Weapon (121), CraftUnit (89, with the AI flight model in .fields),
  Vessel (23, structural component counts), PlayerConfig (24) — the
  full combat balance.
- Character (68 — faction + portrait set), Stage (29 missions:
  location, phases, and the per-stage resource tables it wires up).
- Generic Record / load_records(schema) reads any of the 105 IDXD
  schemas without a bespoke struct.

Each blob = one entity; token[0] names the table, fields are
value-before-key. Named Option<> fields for the common stats + a full
`fields` map; defaulted fields stay None (they're code-resident, not on
disc — honest blanks, never guessed). 8 tests against the real disc.

Examples: iso_map / deep_map census the ISO's formats and IDXD schemas;
dm_extract / dm_rows / dm_roster / mission_map dump the decoded data.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

crates/sylpheed-formats/src/lib.rs

@@ -61,6 +61,8 @@ pub mod movie_manifest;
 
 pub mod movie_voice;
 
+pub mod game_data;
+
 /// Re-export the most commonly used types at the crate root.
 pub use font::FontInfo;
 pub use idxd::{IdxdError, IdxdObject};