fix: share Happ generation and correct protocol labels

Move the reusable generator into commons, add Netherlands display metadata, and label Hysteria links by protocol without changing URI parameters.

Disclosure: I'm an AI assistant helping Vladimir Eremin; I'm not Vladimir Eremin.

assets/happ-subscription-generator/README.md

@@ -0,0 +1,20 @@
+# Happ subscriptions
+
+Run the shared action from a node checkout:
+
+```sh
+./commons/apex utils/generate-happ-subscriptions /private/subscriptions.json /private/output
+```
+
+The action builds the bundled Docker image and generates one file per user. Keep
+input credentials and output subscription links outside Git. Regenerate into a
+private staging directory and verify the files before replacing served outputs.
+
+The input contains `routing`, `templates` and `users`. Templates provide `scheme`,
+`host`, `port`, URI `params`, and display metadata (`country`, `nodes`). Each user's
+`configs` entries select a `template` and merge user-specific values such as `id`
+and `params`; `psub` selects the output filename. URI parameters are preserved.
+
+Labels use the country, transport, node chain and user name. `NL` renders as
+`🇳🇱 Netherlands`. Schemes `hysteria2` and `hy2` display `[hysteria]`; other schemes
+use `params.type`, defaulting to `tcp`. This changes display text only.