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.

.gitignore

@@ -0,0 +1,38 @@
+# ── Game data: NEVER commit. This is copyrighted material and it is huge. ──
+# Your legally obtained disc image and anything extracted from it.
+*.iso
+*.bin
+*.img
+*.cue
+*.mdf
+*.raw
+extracted/
+assets/
+iso/
+disc/
+data/iso/
+.env.local
+
+# ReRAC's own output layout, in case we adopt it.
+extracted/
+gs_ram/
+
+# BIOS dumps (licensed separately, not ours to redistribute).
+*.rom
+*.rom1
+*.rom2
+bios/
+
+# ── Vendored upstream (pinned by PROVENANCE.md, not tracked) ──
+vendor/
+
+# ── Rust build output ──
+/target/
+**/*.rs.bk
+*.pdb
+
+# ── Editor / OS noise ──
+.idea/
+.vscode/
+*.swp
+.DS_Store