Build the Settings module: notification channels, event toggles, DNS badge colors

The Settings page was a "coming soon" placeholder. Port Sloth Manager's
settings feature set: Gotify/ntfy/SMTP/webhook notification channels
(each with its own test-send button), per-event toggles (DNS record
added/updated/deleted, a daily secret-expiry digest with configurable
time/timezone), and per-provider DNS badge color customization.

Settings persist in the existing `settings` key/value table via a new
settingsStore service; a notify service fans a message out to every
enabled channel. DNS record add/update/delete now fire notifications,
and a node-schedule job re-arms itself whenever the notification
settings change. Removed the now-superseded GOTIFY_URL/GOTIFY_TOKEN
env vars in favor of in-app configuration.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

web/src/api/client.ts

@@ -78,6 +78,58 @@ export interface IpamInput {
 
 export type DnsProviderType = "cloudflare" | "loopia" | "pihole" | "azure" | "cpanel" | "technitium";
 
+export interface GotifySettings {
+  enabled: boolean;
+  url: string;
+  token: string;
+  priority: number;
+}
+
+export interface NtfySettings {
+  enabled: boolean;
+  url: string;
+  topic: string;
+  token: string;
+  priority: number;
+}
+
+export interface SmtpSettings {
+  enabled: boolean;
+  host: string;
+  port: number;
+  secure: boolean;
+  username: string;
+  password: string;
+  from: string;
+  to: string;
+}
+
+export interface WebhookSettings {
+  enabled: boolean;
+  url: string;
+  secret: string;
+}
+
+export interface NotificationEvents {
+  dnsAdd: boolean;
+  dnsUpdate: boolean;
+  dnsDelete: boolean;
+  secretCheck: boolean;
+  secretCheckTime: string;
+  timezone: string;
+}
+
+export interface AppSettings {
+  gotify: GotifySettings;
+  ntfy: NtfySettings;
+  smtp: SmtpSettings;
+  webhook: WebhookSettings;
+  notifications: NotificationEvents;
+  providerColors: Record<string, string>;
+}
+
+export type AppSettingsPatch = { [K in keyof AppSettings]?: Partial<AppSettings[K]> };
+
 export interface DnsProviderField {
   key: string;
   label: string;
@@ -534,4 +586,18 @@ export const api = {
       storage: (integrationId: number) => request<SynologyStorageResponse>(`/api/integrations/${integrationId}/synology/storage`),
     },
   },
+  settings: {
+    get: () => request<{ settings: AppSettings }>("/api/settings"),
+    providerColors: () => request<{ providerColors: Record<string, string> }>("/api/settings/provider-colors"),
+    update: (data: AppSettingsPatch) =>
+      request<{ settings: AppSettings }>("/api/settings", { method: "PUT", body: JSON.stringify(data) }),
+    testGotify: (data: { url: string; token: string; priority?: number }) =>
+      request<{ ok: true }>("/api/settings/test-gotify", { method: "POST", body: JSON.stringify(data) }),
+    testNtfy: (data: { url: string; topic: string; token?: string; priority?: number }) =>
+      request<{ ok: true }>("/api/settings/test-ntfy", { method: "POST", body: JSON.stringify(data) }),
+    testSmtp: (data: { host: string; port?: number; secure?: boolean; username?: string; password?: string; from: string; to: string }) =>
+      request<{ ok: true }>("/api/settings/test-smtp", { method: "POST", body: JSON.stringify(data) }),
+    testWebhook: (data: { url: string; secret?: string }) =>
+      request<{ ok: true }>("/api/settings/test-webhook", { method: "POST", body: JSON.stringify(data) }),
+  },
 };