[ECO-2648] Add CDN documentation (#495)

Co-authored-by: alnoki <[email protected]>

src/typescript/example.env

@@ -68,6 +68,20 @@ PUBLISHER_PRIVATE_KEY=""
 # Useful in testing only.
 DB_URL=""
 
+# CDN url
+#
+# See https://github.com/econia-labs/cloud-infra/blob/main/doc/cdn.md on how to
+# set one up.
+#
+# The CDN must include the TradingView library code (see
+# frontend/src/components/charts/const.ts) and the required frontend fonts (see
+# frontend/src/styles/fonts.ts).
+#
+# If not set, you will not be able to build the frontend. However, you will
+# still be able to run `pnpm run dev`, but you will get bizarre fonts and the
+# market page will be unaccessible.
+NEXT_PUBLIC_CDN_URL=""
+
 # Set the API keys for the various frontend networks. It is okay if these are exposed publicly.
 NEXT_PUBLIC_LOCAL_APTOS_API_KEY=""
 NEXT_PUBLIC_CUSTOM_APTOS_API_KEY=""