chore(module-uo): bootstrap repo with governance docs and templates

First commit for the UO module — the game-specific half of the Runic Gateway
website, extracted from core so that core can become game-agnostic. Phase 0 of
the module system plan (docs/website/MODULE_SYSTEM.md §2.7) calls for this repo
to get its initial commit before any module work starts.

Governance scaffolding only; no module code. The design of record settles the
API surface in Phase 1 and Phase 3 is what fills the repo, so writing module
code now would be writing against a contract that does not exist yet.

- README.md          what module-uo is, the phase table, the packaging layout,
                     and why an operator never builds anything
- CONTRIBUTING.md    planning status, the dev loop (a module is not runnable on
                     its own), the zero-internal-imports and one-path-segment
                     rules, schema fragments instead of migrations
- SECURITY.md        private reporting, plus the module-specific notes: the
                     module boundary is not a security boundary, access control
                     lives in core, and the uo-link token stays write-only
- CODE_OF_CONDUCT.md, CONTRIBUTORS.md, LICENSE.md (GPL-3.0-or-later),
  PR + issue templates — the same set every repo in the org carries
- .gitignore         Node-shaped; client/dist/ is ignored deliberately, since it
                     is a release artifact built by CI, not a source artifact

CI lands next, in a PR, mirroring how the installer repo was bootstrapped: an
empty repo cannot take a pull request, but everything after it can.

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

CONTRIBUTORS.md

@@ -0,0 +1,31 @@
+# Contributors
+
+Runic Gateway is built and maintained by the people and tools listed here.
+Thank you to everyone who has contributed.
+
+## Maintainers
+
+- **whitlocktech** <whitlocktech@gmail.com> — project lead and maintainer
+
+## Contributors
+
+<!--
+  Add yourself here when your contribution is merged — alphabetical by name or
+  handle. One line each:
+
+  - **Name or handle** (optional link) — what you contributed
+-->
+
+- _Your name could be here — see [CONTRIBUTING.md](CONTRIBUTING.md)._
+
+## AI-assisted development
+
+Parts of Runic Gateway were developed with the assistance of AI coding tools,
+including **Claude** (Anthropic) via Claude Code. AI-assisted commits are
+attributed in their commit trailers (e.g. `Co-Authored-By: Claude ...`).
+
+In keeping with this project's transparency policy, **all contributors must
+disclose their use of AI tools** on any contribution — see the
+"AI-assisted contributions" section of [CONTRIBUTING.md](CONTRIBUTING.md).
+Disclosed AI assistance is welcome; undisclosed AI-generated contributions are
+not.