init: initial commit

- ticker / QR ad overlay / break slide graphics (1920×1080) with all
  geometry derived from one shared module (src/shared/obs-geometry.mjs)
- OBS scene-collection generator (scripts/generate-obs-scenes.mjs) and a
  read-only in-dashboard setup verifier, both driven by the same module
- en/sr dashboard i18n selected via bundle config; configschema.json with
  neutral first-run defaults seeded from optional branding config
- install.sh / systemd user service / update.sh for venue deployment
- reference OBS scene collection + profile from a real venue as fixtures

CONTRIBUTING.md

@@ -0,0 +1,37 @@
+# Contributing
+
+Thanks for taking a look!
+
+## Setup
+
+The bundle develops inside a NodeCG install:
+
+```sh
+mkdir venue-dev && cd venue-dev
+npm pack nodecg@^2 && tar xzf nodecg-*.tgz --strip-components=1 && rm nodecg-*.tgz
+npm install --omit=dev
+mkdir -p bundles cfg && cd bundles
+git clone https://git.dvdrw.dev/kckljajicevo/nodecg-venue-gfx.git && cd nodecg-venue-gfx
+npm ci
+npm run dev        # watch + auto-restarting NodeCG on :9090
+```
+
+(`scripts/install.sh --local .` automates the same thing.)
+
+## Ground rules
+
+- `dashboard/`, `graphics/`, `extension/` are build outputs — never edit or
+  commit them; sources live in `src/`.
+- Geometry shared with OBS lives only in `src/shared/obs-geometry.mjs`
+  (plain JS + `.d.mts` declarations — keep both in sync).
+- UI strings live in `src/i18n/` — no literals in panel components. New
+  locales: copy `en.ts`, register in `index.ts`, extend the enum in
+  `configschema.json`.
+- `npm run build` and the TypeScript checks must stay green:
+  `npx tsc --noEmit -p src/{dashboard,graphics,extension}/tsconfig.json`.
+- Changes to the generated OBS collection shape should be validated by a real
+  import into OBS ≥ 31.
+
+## License
+
+AGPL-3.0 — contributions are accepted under the same license.