Phase 0: scaffold three-service backend (api/worker/frontend)

api/ (ElysiaJS+Bun WS gateway skeleton), worker/ (Rust, Redis dirty-chunk
stream consumer behind a swappable RenderBackend trait), frontend/
(ElysiaJS+Pug+Tailwind4+Alpine, one server-rendered page) — all three
verified running locally. docker-compose wires them up with postgres,
redis, minio (rendered tile/mesh object storage), and Caddy as reverse
proxy.

THIRD_PARTY_NOTICES.md

@@ -0,0 +1,18 @@
+# Third-party notices
+
+This project may adapt ideas, publicly documented formats, or (rarely) small snippets from
+other open-source projects (e.g. squaremap/Dynmap/BlueMap map-serving patterns, JourneyMap's
+public waypoint-link documentation), always with attribution here and a comment at the point of
+use. Nothing is copied from closed-source projects — in particular, Xaero's Minimap/Worldmap are
+closed-source, so any Xaero-compatible waypoint link support is implemented purely from publicly
+documented/community-reverse-engineered wire format, never from Xaero's code.
+
+No third-party code has been adapted yet. Entries will be added here as they land, in the form:
+
+```
+## <thing adapted>
+- Source: <project name and URL>
+- License: <license>
+- Used in: <file path>
+- What was adapted: <short description>
+```