fix(favicon): скругляем углы кастомного лого как у плитки в хедере

Кастомное лого квадратное, и в фавиконе показывалось с острыми углами. Теперь
лого прогоняется через canvas со скруглённым клипом (radiusRatio 0.3 — как
rounded-linear-lg 12px на плитке 40px в хедере) и отдаётся скруглённым PNG.
При сбое canvas (taint/нет 2d-контекста) — фолбэк на сырой лого. Применяется и
в кабинете (useBranding), и на лендинге (QuickPurchase); буквенная монограмма
уже скруглена через rx.

src/hooks/useBranding.ts

@@ -9,7 +9,7 @@ import {
   preloadLogo,
   isLogoPreloaded,
 } from '@/api/branding';
-import { setFavicon, letterFaviconDataUri } from '@/utils/favicon';
+import { setFavicon, letterFaviconDataUri, roundedFaviconDataUri } from '@/utils/favicon';
 
 const FALLBACK_NAME = import.meta.env.VITE_APP_NAME || 'Cabinet';
 const FALLBACK_LOGO = import.meta.env.VITE_APP_LOGO || 'V';
@@ -43,10 +43,20 @@ export function useBranding() {
     document.title = appName || 'VPN';
   }, [appName]);
 
-  // Update favicon — custom logo when available, else a brand-letter monogram
-  // so the tab always carries an icon instead of the browser default.
+  // Update favicon — custom logo (rounded like the header tile) when available,
+  // else a brand-letter monogram so the tab always carries an icon.
   useEffect(() => {
-    setFavicon(logoUrl || letterFaviconDataUri(logoLetter));
+    if (!logoUrl) {
+      setFavicon(letterFaviconDataUri(logoLetter));
+      return;
+    }
+    let cancelled = false;
+    roundedFaviconDataUri(logoUrl).then((rounded) => {
+      if (!cancelled) setFavicon(rounded || logoUrl);
+    });
+    return () => {
+      cancelled = true;
+    };
   }, [logoUrl, logoLetter]);
 
   // Fullscreen setting from server

src/pages/QuickPurchase.tsx

@@ -30,7 +30,7 @@ import LanguageSwitcher from '../components/LanguageSwitcher';
 import { cn } from '../lib/utils';
 import { getApiErrorMessage } from '../utils/api-error';
 import { formatPrice } from '../utils/format';
-import { setFavicon, letterFaviconDataUri } from '../utils/favicon';
+import { setFavicon, letterFaviconDataUri, roundedFaviconDataUri } from '../utils/favicon';
 import { useCurrency } from '../hooks/useCurrency';
 
 function detectContactType(value: string): 'email' | 'telegram' {
@@ -805,7 +805,18 @@ export default function QuickPurchase() {
   useEffect(() => {
     if (!branding) return;
     const logoUrl = branding.has_custom_logo ? getLogoBlobUrl() : null;
-    setFavicon(logoUrl || letterFaviconDataUri(branding.logo_letter));
+    if (!logoUrl) {
+      setFavicon(letterFaviconDataUri(branding.logo_letter));
+      return;
+    }
+    let cancelled = false;
+    // Round the custom logo like the header tile instead of a hard square.
+    roundedFaviconDataUri(logoUrl).then((rounded) => {
+      if (!cancelled) setFavicon(rounded || logoUrl);
+    });
+    return () => {
+      cancelled = true;
+    };
   }, [branding]);
 
   const [discountExpired, setDiscountExpired] = useState(false);

src/utils/favicon.ts

@@ -33,3 +33,62 @@ export function letterFaviconDataUri(letter: string): string {
     `</svg>`;
   return `data:image/svg+xml,${encodeURIComponent(svg)}`;
 }
+
+/**
+ * Render `src` (e.g. a square custom logo) into a rounded-corner PNG data URI
+ * so the favicon gets the same rounded tile as the header logo, instead of
+ * hard square corners.
+ *
+ * `radiusRatio` 0.3 mirrors the header tile (rounded-linear-lg = 12px on a 40px
+ * tile). Returns null if the image can't be loaded or the canvas is tainted —
+ * the caller should fall back to the raw `src`.
+ */
+export async function roundedFaviconDataUri(
+  src: string,
+  size = 64,
+  radiusRatio = 0.3,
+): Promise<string | null> {
+  if (!src) return null;
+  try {
+    const img = await loadImage(src);
+    const canvas = document.createElement('canvas');
+    canvas.width = size;
+    canvas.height = size;
+    const ctx = canvas.getContext('2d');
+    if (!ctx) return null;
+
+    traceRoundedRect(ctx, size, size * radiusRatio);
+    ctx.clip();
+
+    // object-fit: cover — fill the rounded tile, center-cropping any overflow.
+    const scale = Math.max(size / img.width, size / img.height);
+    const dw = img.width * scale;
+    const dh = img.height * scale;
+    ctx.drawImage(img, (size - dw) / 2, (size - dh) / 2, dw, dh);
+
+    return canvas.toDataURL('image/png');
+  } catch {
+    return null;
+  }
+}
+
+function loadImage(src: string): Promise<HTMLImageElement> {
+  return new Promise((resolve, reject) => {
+    const img = new Image();
+    img.onload = () => resolve(img);
+    img.onerror = reject;
+    img.src = src;
+  });
+}
+
+/** Trace a centered square rounded-rect path of side `size` and corner `r`. */
+function traceRoundedRect(ctx: CanvasRenderingContext2D, size: number, r: number): void {
+  const radius = Math.min(r, size / 2);
+  ctx.beginPath();
+  ctx.moveTo(radius, 0);
+  ctx.arcTo(size, 0, size, size, radius);
+  ctx.arcTo(size, size, 0, size, radius);
+  ctx.arcTo(0, size, 0, 0, radius);
+  ctx.arcTo(0, 0, size, 0, radius);
+  ctx.closePath();
+}