Initialise native Rust port of Ratchet & Clank: Going Commando

Sets up the foundation for reimplementing the PS2 game in Rust rather than
emulating it. Nothing is implemented yet; this is the scaffold, the verified
target and the working agreements that keep a long project coherent.

Target disc, verified against a real image:

  SCUS_972.68 v1.01, USA Black Label, NTSC 60 Hz
  boot ELF 2,618,684 bytes, SHA-1 bacda860...d098a77, entry 0x00131AE8

The entry point independently matches the value recorded by the rac2-gc-decomp
community reference, which cross-confirms the identification. This is the exact
build the upstream research pins; Greatest Hits v2.00 is a different binary and
is not the target. NTSC matters beyond label compatibility: PAL discs run 50 Hz,
which would make chargeboots and other speed-sensitive movement run at 5/6
speed. Verifying the disc before writing movement code avoids discovering that
in Phase 5.

Contents:

- Five-crate workspace (formats, extract, game, video, engine) on Bevy 0.19.1,
  matching the version ReRAC uses so its Graphics Synthesizer and VU work stays
  portable. `cargo check --workspace` is clean.

- tools/identify-disc.py, which reproduces the identification against any
  disc image and distinguishes a truncated dump from a non-PS2 image.

- .githooks/pre-commit, refusing game data from entering git history: disc
  image extensions, asset directories, container signatures at offset 0, and
  files over 50 MiB. Verified against seven cases including a disc image
  renamed to look like source. Now that this pushes to a remote, this matters
  more than it would have locally.

- AGENTS.md, the operating agreements: no game data ever, reproduce the PS2
  float model rather than approximating it, bound every read, verify against
  the real disc.

- PROVENANCE.md, recording that this follows ReRAC (ISC) and learns from
  rac2-gc-decomp (MIT). Wrench is used as a written specification only and no
  GPLv3 code is copied, since that would relicense everything derived from it.
  RAC2Decomp is explicitly not used: its provenance is disputed in the upstream
  community reference, and it targets the wrong region.

- docs/roadmap.md, phased so the riskiest unknowns are retired early. The two
  that matter: overlay relocation transfers from ReRAC and makes 27 level
  overlays tractable, while VU1 microcode is binary and is the hardest single
  item. Phase 5 is a deliberately scoped Veldin vertical slice as the go/no-go.

crates/gc-formats/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "gc-formats"
+version.workspace = true
+edition.workspace = true
+rust-version.workspace = true
+license.workspace = true
+publish.workspace = true
+description = "Parsers for Ratchet & Clank: Going Commando (PS2) asset formats"
+
+[dependencies]
+anyhow.workspace = true
+thiserror.workspace = true
+bytemuck.workspace = true
+sha1.workspace = true
+
+[dev-dependencies]

crates/gc-formats/src/lib.rs

@@ -0,0 +1,38 @@
+//! Asset format parsers for *Ratchet & Clank: Going Commando* (PS2).
+//!
+//! Target: `SCUS_972.68` v1.01, USA Black Label, NTSC 60 Hz. See
+//! `docs/disc-identification.md`.
+//!
+//! This crate reads data structures out of the game and produces plain Rust
+//! values. It performs no rendering, no simulation and no I/O beyond what the
+//! caller hands it, which keeps every parser testable against a byte slice.
+//!
+//! # What belongs here
+//!
+//! * `iso9660`     - the disc filesystem. R&C2 lists its assets as real files,
+//!                   unlike R&C1, so enumeration works.
+//! * `hdr`         - `RC2.HDR`, the table of contents (408,444 bytes at the
+//!                   disc root). The engine addresses assets by sector, and
+//!                   this is where those sector numbers come from.
+//! * `wad`         - Insomniac's LZ77 container (`WAD` magic, 16-byte header).
+//!                   Carries level core data, audio and video streams.
+//! * `tfrag`       - terrain fragments: LOD chains, strips, morph targets.
+//! * `tie`         - instanced environment geometry ("ties"), with fat vertices.
+//! * `shrub`       - instanced foliage and decorative meshes.
+//! * `moby`        - dynamic actors, including Ratchet, enemies and crates.
+//! * `moby_anim`   - skeletal animation: sequences, frames, blending.
+//! * `collision`   - the collision world: cells, packed vertices, faces.
+//! * `occlusion`   - the PVS grid used for visibility.
+//! * `sky`, `volumes`, `textures` - sky shells, fog volumes, CSM1 textures.
+//!
+//! # Rules
+//!
+//! **Bound every read.** Malformed data must produce a typed error, never a
+//! panic and never a read past the end of the buffer.
+//!
+//! **No game data in this repository.** Parsers are written against a copy of
+//! your own legally obtained disc, and the extracted output stays outside git.
+//!
+//! **Verify against the real thing.** Every parser gets a test that loads
+//! known-good bytes from your disc and checks the parsed result. See
+//! `docs/formats/` for the specs being implemented.