refactor: drop toast + over-engineered extras, add inline admin feedback

Phase 1 cleanup of the personal-site revamp. Backend/architecture untouched;
changes are limited to removing unused complexity and restoring feedback.

Removals
- Toast system: delete react-hot-toast, Toaster, QueryToastBridge, lib/toast,
  the toggle/easter-egg calls, related i18n keys and the dependency.
- Contact protection: remove Turnstile + per-IP rate limiting
  (lib/contact-guard, lib/contact-protection, admin screen, form widget,
  app-config wiring, nav entry, test).
- Speculative specs: delete orders, products, downloads, project-inquiry.

Inline feedback (replaces toast, no new deps)
- Add lib/admin-feedback (withFlash/readFlash) and components/admin/admin-flash,
  rendered centrally by AdminDashboardShell.
- Emit success/error messages for media, site-settings, portfolio, smtp,
  marquee and maintenance actions; pages read them via searchParams.
- Contact form shows validation/delivery errors inline; success still
  redirects to /success.

Docs
- Fix stale paths in frontend-system-* (components/root -> components/admin,
  lib/root-navigation -> lib/admin-navigation, drop phantom src/) and remove
  contact-protection references from docs and CLAUDE.md.
- Add docs/PHASE0_DIAGNOSIS.md (diagnosis report).

Note: proxy.ts self-fetch kept intentionally; it also drives maintenance mode.

app/_admin/smtp/actions.ts

@@ -6,6 +6,7 @@ import { isRedirectError } from "next/dist/client/components/redirect-error";
 
 import { getAdminAppPath, toInternalAdminPath } from "@/lib/admin-routing";
 import { clearAdminSessionCookie, isAdminAuthenticated } from "@/lib/admin-auth";
+import { withFlash } from "@/lib/admin-feedback";
 import { isCheckedFormValue } from "@/lib/form-data";
 import {
   getMailSettings,
@@ -21,12 +22,6 @@ async function ensureAdmin() {
   }
 }
 
-function withMessage(pathname: string, type: "success" | "error", message: string) {
-  const params = new URLSearchParams();
-  params.set(type, message);
-
-  return `${pathname}?${params.toString()}`;
-}
 
 function parsePort(value: string) {
   const port = Number.parseInt(value, 10);
@@ -79,7 +74,7 @@ export async function saveMailSettingsAction(formData: FormData) {
 
     await updateMailSettings(nextMailSettings);
     revalidatePath(toInternalAdminPath("/smtp"));
-    redirect(withMessage(getAdminAppPath("/smtp"), "success", "SMTP Einstellungen gespeichert."));
+    redirect(withFlash(getAdminAppPath("/smtp"), { success: "SMTP Einstellungen gespeichert." }));
   } catch (error) {
     if (isRedirectError(error)) {
       throw error;
@@ -90,7 +85,7 @@ export async function saveMailSettingsAction(formData: FormData) {
         ? error.message
         : "SMTP Einstellungen konnten nicht gespeichert werden.";
 
-    redirect(withMessage(getAdminAppPath("/smtp"), "error", message));
+    redirect(withFlash(getAdminAppPath("/smtp"), { error: message }));
   }
 }
 
@@ -99,7 +94,7 @@ export async function sendTestEmailAction() {
 
   try {
     await sendTestEmail();
-    redirect(withMessage(getAdminAppPath("/smtp"), "success", "Test-E-Mail gesendet."));
+    redirect(withFlash(getAdminAppPath("/smtp"), { success: "Test-E-Mail gesendet." }));
   } catch (error) {
     if (isRedirectError(error)) {
       throw error;
@@ -110,6 +105,6 @@ export async function sendTestEmailAction() {
         ? error.message
         : "Test-E-Mail konnte nicht gesendet werden.";
 
-    redirect(withMessage(getAdminAppPath("/smtp"), "error", message));
+    redirect(withFlash(getAdminAppPath("/smtp"), { error: message }));
   }
 }

app/_admin/smtp/contact-protection/actions.ts

@@ -1,112 +0,0 @@
-"use server";
-
-import { revalidatePath } from "next/cache";
-import { redirect } from "next/navigation";
-import { isRedirectError } from "next/dist/client/components/redirect-error";
-
-import { getAdminAppPath, toInternalAdminPath } from "@/lib/admin-routing";
-import { clearAdminSessionCookie, isAdminAuthenticated } from "@/lib/admin-auth";
-import { isCheckedFormValue } from "@/lib/form-data";
-import {
-  getContactProtectionSettings,
-  updateContactProtectionSettings,
-} from "@/lib/app-config";
-import type { ContactProtectionSettings } from "@/lib/contact-protection";
-
-async function ensureAdmin() {
-  if (!(await isAdminAuthenticated())) {
-    await clearAdminSessionCookie();
-    redirect(getAdminAppPath("/"));
-  }
-}
-
-function withMessage(pathname: string, type: "success" | "error", message: string) {
-  const params = new URLSearchParams();
-  params.set(type, message);
-
-  return `${pathname}?${params.toString()}`;
-}
-
-function parseCount(value: string, fallback: number, label: string) {
-  const parsed = Number.parseInt(value || String(fallback), 10);
-
-  if (!Number.isInteger(parsed) || parsed <= 0) {
-    throw new Error(`${label} must be a positive number.`);
-  }
-
-  return parsed;
-}
-
-function parseContactProtectionFormData(
-  formData: FormData,
-  existingSettings: ContactProtectionSettings,
-): ContactProtectionSettings {
-  const turnstileEnabled = isCheckedFormValue(formData.get("turnstileEnabled"));
-  const turnstileSiteKey = String(formData.get("turnstileSiteKey") ?? "").trim();
-  const turnstileSecretKey = String(formData.get("turnstileSecretKey") ?? "");
-  const rateLimitEnabled = isCheckedFormValue(formData.get("contactRateLimitEnabled"));
-
-  if (turnstileEnabled && !turnstileSiteKey) {
-    throw new Error("Turnstile site key is required when Turnstile is enabled.");
-  }
-
-  if (turnstileEnabled && !turnstileSecretKey.trim() && !existingSettings.turnstile.secretKey) {
-    throw new Error("Turnstile secret key is required when Turnstile is enabled.");
-  }
-
-  return {
-    turnstile: {
-      enabled: turnstileEnabled,
-      siteKey: turnstileSiteKey,
-      secretKey: turnstileSecretKey.trim()
-        ? turnstileSecretKey
-        : existingSettings.turnstile.secretKey,
-    },
-    rateLimit: {
-      enabled: rateLimitEnabled,
-      maxRequests: parseCount(
-        String(formData.get("contactRateLimitMaxRequests") ?? ""),
-        existingSettings.rateLimit.maxRequests,
-        "Rate limit max requests",
-      ),
-      windowMinutes: parseCount(
-        String(formData.get("contactRateLimitWindowMinutes") ?? ""),
-        existingSettings.rateLimit.windowMinutes,
-        "Rate limit window minutes",
-      ),
-    },
-  };
-}
-
-export async function saveContactProtectionSettingsAction(formData: FormData) {
-  await ensureAdmin();
-
-  try {
-    const existingSettings = await getContactProtectionSettings();
-    const nextSettings = parseContactProtectionFormData(formData, existingSettings);
-
-    await updateContactProtectionSettings(nextSettings);
-    revalidatePath(toInternalAdminPath("/smtp/contact-protection"));
-    revalidatePath("/contact");
-    revalidatePath("/ar/contact");
-    revalidatePath("/en/contact");
-    redirect(
-      withMessage(
-        getAdminAppPath("/smtp/contact-protection"),
-        "success",
-        "Contact Protection gespeichert.",
-      ),
-    );
-  } catch (error) {
-    if (isRedirectError(error)) {
-      throw error;
-    }
-
-    const message =
-      error instanceof Error
-        ? error.message
-        : "Contact Protection konnte nicht gespeichert werden.";
-
-    redirect(withMessage(getAdminAppPath("/smtp/contact-protection"), "error", message));
-  }
-}

app/_admin/smtp/contact-protection/page.tsx

@@ -1,62 +0,0 @@
-import { redirect } from "next/navigation";
-
-import { MotionFade } from "@/components/motion-fade";
-import { ContactProtectionForm } from "@/components/admin/contact-protection-form";
-import { AdminDashboardShell } from "@/components/admin/admin-dashboard-shell";
-import { clearAdminSessionCookie, isAdminAuthenticated } from "@/lib/admin-auth";
-import { getAdminAppPath } from "@/lib/admin-routing";
-import { getContactProtectionFormValues } from "@/lib/app-config";
-
-import { saveContactProtectionSettingsAction } from "./actions";
-
-export const dynamic = "force-dynamic";
-
-const copy = {
-  title: "Contact Protection",
-  subtitle: "Turnstile und Rate Limiting fuer das Kontaktformular.",
-  overview: "Uebersicht",
-  maintenance: "Wartungsmodus",
-  uiKit: "UI Kit",
-  media: "Media",
-  siteSettings: "Settings",
-  smtp: "SMTP",
-  contactProtection: "Contact Protection",
-  portfolio: "Portfolio",
-  logout: "Ausloggen",
-  backToSite: "Zur Website",
-};
-
-export default async function AdminSMTPProtectionPage() {
-  if (!(await isAdminAuthenticated())) {
-    redirect(getAdminAppPath("/"));
-  }
-
-  async function logoutAction() {
-    "use server";
-
-    await clearAdminSessionCookie();
-    redirect(getAdminAppPath("/"));
-  }
-
-  const settings = await getContactProtectionFormValues();
-
-  return (
-    <AdminDashboardShell
-      copy={copy}
-      active="smtp"
-      smtpChild="contact-protection"
-      logoutAction={logoutAction}
-      headerTitle={copy.title}
-      headerDescription={copy.subtitle}
-    >
-      <div className="space-y-6">
-        <MotionFade delay={0.16}>
-          <ContactProtectionForm
-            action={saveContactProtectionSettingsAction}
-            initialSettings={settings}
-          />
-        </MotionFade>
-      </div>
-    </AdminDashboardShell>
-  );
-}

app/_admin/smtp/page.tsx

@@ -2,6 +2,7 @@ import { redirect } from "next/navigation";
 
 import { MotionFade } from "@/components/motion-fade";
 import { AdminDashboardShell } from "@/components/admin/admin-dashboard-shell";
+import { readFlash } from "@/lib/admin-feedback";
 import { SMTPSettingsForm } from "@/components/admin/smtp-settings-form";
 import { Button } from "@/components/ui/button";
 import { clearAdminSessionCookie, isAdminAuthenticated } from "@/lib/admin-auth";
@@ -21,13 +22,18 @@ const copy = {
   media: "Media",
   siteSettings: "Settings",
   smtp: "SMTP",
-  contactProtection: "Contact Protection",
   portfolio: "Portfolio",
   logout: "Ausloggen",
   backToSite: "Zur Website",
 };
 
-export default async function AdminSMTPPage() {
+export default async function AdminSMTPPage({
+  searchParams,
+}: {
+  searchParams?: Promise<{ success?: string; error?: string }>;
+}) {
+  const flash = readFlash(await searchParams);
+
   if (!(await isAdminAuthenticated())) {
     redirect(getAdminAppPath("/"));
   }
@@ -45,7 +51,7 @@ export default async function AdminSMTPPage() {
     <AdminDashboardShell
       copy={copy}
       active="smtp"
-      smtpChild="settings"
+      flash={flash}
       logoutAction={logoutAction}
       headerTitle={copy.title}
       headerDescription={copy.subtitle}