Add sen:// subscription with master keys

A master key is a sen:// link with a device limit. Each device
generates its own WireGuard keypair and registers only the public key,
then polls a signed /sub/v1/config, so params and generation changes
reach users without re-importing a key.

- awg-ctrl: peers table and /api/peers*, /api/profile; nextIp and
  rebuildConf take peers into account (output unchanged without them)
- awg-ui: link codec and signatures (sen.ts), registry, panel routes
  and the public listener on SUB_PORT (sub.ts)
- responses are always Ed25519-signed; TLS with a pinned self-signed
  certificate is optional
- devices report a client version, shown as platform-version
- "Мастер-ключи" tab: a table with the devices nested under each key,
  a device-limit meter, per-key settings and a placeholder for the
  servers a key serves; cards on mobile
- install.sh/CLI: subscription signing key, optional certificate, port;
  kept across reinstalls with KEEP_DATA
- add the missing mock-server.ts used by npm run dev:mock

awg-ui/src/components/icons.tsx

@@ -35,6 +35,13 @@ export const IcoRefresh = () => (
         <path d="M20.49 15a9 9 0 1 1-2.12-9.36L23 10"/>
     </svg>
 );
+export const IcoSettings = () => (
+    <svg width="15" height="15" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round">
+        <line x1="4" y1="7" x2="20" y2="7"/><line x1="4" y1="17" x2="20" y2="17"/>
+        <circle cx="9" cy="7" r="2.5" fill="var(--surface-bright, transparent)"/>
+        <circle cx="15" cy="17" r="2.5" fill="var(--surface-bright, transparent)"/>
+    </svg>
+);
 export const IcoQR = () => (
     <svg width="15" height="15" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
         <rect x="3" y="3" width="7" height="7" rx="1"/><rect x="14" y="3" width="7" height="7" rx="1"/>