Server keys in etc/, bind in docker compose

- bin/gen-server-keys.sh: generate Ed25519 keypair to etc/server-service.{pub,key,env}
- main.go: read keys from file (ADMIN_PUBLIC_KEY_FILE) when env empty
- docker-compose: env_file etc/server-service.env, mount etc/
- bin/up.sh: auto-run gen-server-keys if etc/server-service.env missing
- ErrRegistrationNotConfigured for clearer 503 when keys not set
- etc/README.md, etc/.gitignore
- bin/gen-admin-key.sh for one-off key gen
- .env.example

Made-with: Cursor

web/app.js

@@ -47,7 +47,7 @@ createApp({
         try {
           await client.registerBySigningServiceKey(state.publicKey, state.privateKey);
         } catch (err) {
-          if (!err.message.includes("already registered") && !err.message.includes("not configured")) {
+          if (!err.message.includes("already registered") && !err.message.includes("not configured") && !err.message.includes("ADMIN_PUBLIC_KEY")) {
             throw err;
           }
           // Proceed to login: already registered or registration disabled (invitation flow)