Add register-by-signature, web fixes, bin scripts, docs

- Register by signing service key: GET /v1/service-key, POST /v1/auth/register-by-signature
- Login auto-attempts register first for new users
- Web: default API URL momswap.produktor.duckdns.org, /libs/ static handler
- Docker: webbuild stage for geo-api-client, copy web+libs to runtime
- Bin scripts: test.sh, run.sh, up.sh, down.sh
- docs/ed25519-security-use-cases.md: use cases, message formats, examples
- SERVICE_PUBLIC_KEY env (defaults to ADMIN_PUBLIC_KEY)

Made-with: Cursor

web/index.html

@@ -39,6 +39,7 @@
                 <v-btn color="secondary" @click="ensureKeys">Ensure Keys in localStorage</v-btn>
                 <v-textarea v-model="state.publicKey" class="mt-3" label="Public Key" rows="2"></v-textarea>
                 <v-textarea v-model="state.privateKey" label="Private Key (local only)" rows="2"></v-textarea>
+                <v-btn color="secondary" class="mt-2" @click="register">Register (sign service key)</v-btn>
                 <v-btn color="success" class="mt-2" @click="login">Login</v-btn>
               </v-card>
             </v-col>