docs(reference): adopt the last reference files from the project root

Three untracked files in the project root had no home in either repository:

- the Xbox 360 technical reference report (a research compilation) becomes
  docs/reference/xbox360-re-technical-reference.md, unchanged;
- XBOX360_ARCHITECTURE.md becomes docs/reference/xbox360-architecture.md,
  trimmed to its platform facts. Its format "status" sections (PAK unknown,
  mesh unknown, audio TODO) and the `just sniff` workflow predate every
  decoder in this repo and were wrong;
- generate_export_docs.py becomes tools/generate_export_docs.py, the path the
  committed xbox360-exports.* already name as their generator. It lived
  inside a Canary checkout, so it now takes --canary and --out and fails
  loudly on a tree that is not Canary.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

docs/reference/README.md

@@ -13,6 +13,12 @@ repository or as an untracked file on one disk, which is the same as not existin
 | `xex2-format.md` | the XEX2 container format | `xex2tractor`, byte-identical |
 | `xbox360-exports.{json,md}` | 2,913 system exports across `xboxkrnl.exe`, `xam.xex`, `xbdm.xex` | `xex2tractor`, byte-identical |
 | `ppc-instructions.{json,md}` | the PowerPC instruction reference | untracked, project root |
+| `xbox360-re-technical-reference.md` | a research compilation on the whole platform: CPU, GPU, XDVDFS, STFS, XEX2, kernel, XMA, security | untracked, project root |
+| `xbox360-architecture.md` | a one-page platform quick reference, trimmed to its platform facts | untracked, project root |
+
+`xbox360-exports.{json,md}` can be regenerated from a Canary checkout with
+`python3 tools/generate_export_docs.py` (adopted from the same project root). The
+committed copies come from an older Canary, so a fresh run changes a few statuses.
 
 `LICENSE` at the repository root came from the same place — MIT, and this
 repository had none at all.