docs(modules): add the Rust Oxide/uMod API reference for module-rust

Mirrors uMod's Rust game API into docs/modules/rust/ so the upcoming
module-rust can be designed against it without a round trip upstream.

- HOOKS.md: all 477 hooks in 20 categories, scraped verbatim from
  umod.org/documentation/games/rust. Each entry keeps its description,
  its return contract, its tags and every C# overload uMod publishes.
  Opens with a category table and a full alphabetical index
  (name -> category -> return contract).
- DEFINITIONS.md: 678 items (short name, item id, display name) and
  2,590 workshop skin ids across 104 items.
- README.md: why the reference exists, how an Oxide hook actually binds
  (by name and arity, by reflection - a typo is silently never called),
  the four return contracts, and how the bridge invariants restate
  against Oxide. Records provenance and the exact refresh procedure:
  the hooks JSON endpoint is not Cloudflare-gated even though the HTML
  page is, and the definitions page has to come out of a browser.

The mirror is reference only - uMod stays upstream and normative, and
nothing here is a Runic Gateway contract. Rust wipes monthly, so both
files carry their capture date (2026-09-15) and a re-capture note.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016wDDVXWMDz82WqE1i969r4

README.md

@@ -56,6 +56,7 @@ particular game; a module is what makes it a site *for* one.
 | [uo/API.md](modules/uo/API.md) · [uo/SCHEMA.md](modules/uo/SCHEMA.md) | module-uo's own route surface and the tables it owns |
 | [kit-acceptance.md](modules/kit-acceptance.md) | The Integration Kit acceptance run — building a module by following the kit alone, and what it found |
 | [rust-dryrun.md](modules/rust-dryrun.md) | A written, deliberately unimplemented `module-rust` — the test that the module contract generalises past the game it was extracted from |
+| [rust/](modules/rust/README.md) | **Reference for the upcoming `module-rust`** — a mirror of uMod's Rust Oxide API, scraped from upstream: [HOOKS.md](modules/rust/HOOKS.md) (all 477 hooks) and [DEFINITIONS.md](modules/rust/DEFINITIONS.md) (678 items, 2,590 skins) |
 
 ### `link/`
 | Doc | What it covers |