refactor: codebase opschoning — type safety, error handling, central config, page splits

- categorie A: alle catch(e: any) → catch(e: unknown) met instanceof check
- categorie B: stille .catch() logging toegevoegd (SWRegister, admin, upload, auth)
- categorie C: hardcoded 192.168.1.176 IPs vervangen door env var defaults
- categorie D: page files >250L gesplitst (history, settings, explorer, admin/payment,
  ipns, users, upload, dashboard) in helpers/components
- categorie E: eslint-disable vervangen in SearchInput.tsx
- src/lib/config.ts centrale config module (localhost defaults)
- CSP in next.config.ts dynamisch via env var
- deploy.sh: geen hardcoded IP meer (REQUIRED arg)
- lib/api/ lib/auth/ lib/wallet/ lib/search-index/ lib/storage/ gesplitst in modules
- ongebruikte bestanden verwijderd: api.ts, auth.tsx, wallet.ts, search-index.ts,
  PaymentPanel.tsx, SearchBar.tsx, proxy.ts, serve-static.js

src/app/settings/helpers.ts

@@ -0,0 +1,44 @@
+/* ── Settings Page Helpers ── */
+
+import type { PortalSettings } from "@/lib/storage";
+
+export function formatStorageMB(mb: number): string {
+  if (mb >= 1024) return (mb / 1024).toFixed(0) + " GB";
+  return mb + " MB";
+}
+
+export function inputCls(field: string, validation: Record<string, string | null>): string {
+  return `w-full rounded-lg bg-surface-900 border ${
+    validation[field] ? "border-accent-rose/50" : "border-surface-700"
+  } px-3 py-2 text-sm text-surface-200 placeholder:text-surface-500 focus:outline-none focus:border-brand-500 focus:ring-1 focus:ring-brand-500 transition-colors`;
+}
+
+export function validateSettings(
+  form: PortalSettings,
+): { valid: boolean; errors: Record<string, string | null> } {
+  const errors: Record<string, string | null> = {};
+  let valid = true;
+
+  if (!form.gatewayUrl.startsWith("http://") && !form.gatewayUrl.startsWith("https://")) {
+    errors.gatewayUrl = "Must start with http:// or https://";
+    valid = false;
+  }
+  if (form.gatewayUrl.length > 500) {
+    errors.gatewayUrl = "Too long (max 500 chars)";
+    valid = false;
+  }
+  if (form.apiEndpoint && !form.apiEndpoint.startsWith("/") && !form.apiEndpoint.startsWith("http")) {
+    errors.apiEndpoint = "Must be empty, a path (/…), or a URL";
+    valid = false;
+  }
+  if (form.storageMax < 1 || form.storageMax > 102400) {
+    errors.storageMax = "Must be 1–102400 MB";
+    valid = false;
+  }
+  if (form.refreshInterval < 5 || form.refreshInterval > 300) {
+    errors.refreshInterval = "Must be 5–300 seconds";
+    valid = false;
+  }
+
+  return { valid, errors };
+}