system: information panel and event log; about: download this build's source

System page laid out after 3CX's admin dashboard: a System information panel (version,
host name, company, public IP, LAN IPs, ports, telephony, restart needed, copy buttons,
how to restart) and an Event log panel (system_events, 90 days: trunk down/up, Asterisk
down/up, restart needed, config failed, 911, public IP changed, backups, disk) with Load
more and a CSV download.

About (/about, no sign-in, linked from the login page, My phone and System): AGPL-3.0
notice, credits, the repository link, and "Code v<version>", which downloads
selfphone.tar.gz: the api image now tars its own build context (no .env, data,
node_modules, build output or .git) before installing anything.

Task: M11-T7

packages/shared/src/settings.ts

@@ -110,3 +110,35 @@ export type BackupDto = { name: string; size: number; createdAt: string };
 /** GET /api/system/tls: the SIP TLS certificate in data/tls (M11-T2). */
 export type TlsCert =
   { ok: true; subject: string; names: string[]; notAfter: string } | { ok: false; error: string };
+
+/** GET /api/system/status: the System page's "System information" (05 §2). */
+export type SystemStatus = {
+  version: string;
+  hostname: string;
+  companyName: string;
+  publicIp: string | null;
+  /** Re-checked every 5 minutes (network.publicIpWatch). */
+  publicIpDynamic: boolean;
+  lanIps: string[];
+  ports: { sip: number; sipTcp: boolean; sips: number | null; rtp: string; https: number };
+  ami: { connected: boolean };
+  restartRequired: boolean;
+};
+
+/** GET /api/system/events: the System page's event log, newest first. */
+export type SystemEventDto = {
+  id: number;
+  createdAt: string;
+  severity: 'info' | 'warning' | 'error';
+  code: string;
+  source: string;
+  message: string;
+};
+
+/** GET /api/about (no sign-in): what runs here and where its source is (AGPL, 08 §4). */
+export type AboutDto = {
+  version: string;
+  repoUrl: string;
+  /** The source this build was made from (selfphone.tar.gz); null outside a Docker build. */
+  source: { bytes: number; builtAt: string } | null;
+};