Add COSS toast notifications and swap in the new logo

Wire COSS's (Base UI) Sonner-style stacked toast into the app:

- Install @coss/toast (components/ui/toast.tsx) and mount <ToastProvider> in
  the root layout; add a small notify.{success,error,info,warning} helper
  (lib/toast.ts) over toastManager so callers don't repeat the toast shape.
- Toast on the events requested: clinic created (onboarding), auth actions
  (sign in / sign up / sign out / password reset request + reset), patient
  saved (create/edit), and all failure branches as error toasts (kept inline
  errors as a fallback). New auth toast strings added to the en translation.
- Replace the logo everywhere: overwrite public/temetro-logo.png with the new
  1024² square mark (same aspect ratio as the old 500², so existing 32×32
  next/image usages stay undistorted; no reference changes needed).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/app/globals.css

@@ -59,7 +59,51 @@
     background-position: -200% 0;
     }
   }
-}
+  --animate-toast-success-odd: toast-success-odd 0.32s cubic-bezier(0.5, 1, 0.89, 1);
+  --animate-toast-success-even: toast-success-even 0.32s cubic-bezier(0.5, 1, 0.89, 1);
+  --animate-toast-error-odd: toast-error-odd 0.28s cubic-bezier(0.5, 1, 0.89, 1);
+  --animate-toast-error-even: toast-error-even 0.28s cubic-bezier(0.5, 1, 0.89, 1)
+;
+  @keyframes toast-success-odd {
+  0% {
+    scale: 1;}
+  30% {
+    scale: 1.025;}
+  60% {
+    scale: 0.99;}
+  100% {
+    scale: 1;}}
+  @keyframes toast-error-odd {
+  0% {
+    translate: 0 0;}
+  25% {
+    translate: -3px 0;}
+  50% {
+    translate: 3px 0;}
+  75% {
+    translate: -3px 0;}
+  100% {
+    translate: 0 0;}}
+  @keyframes toast-success-even {
+  0% {
+    scale: 1;}
+  30% {
+    scale: 1.025;}
+  60% {
+    scale: 0.99;}
+  100% {
+    scale: 1;}}
+  @keyframes toast-error-even {
+  0% {
+    translate: 0 0;}
+  25% {
+    translate: -3px 0;}
+  50% {
+    translate: 3px 0;}
+  75% {
+    translate: -3px 0;}
+  100% {
+    translate: 0 0;}}}
 
 :root {
   --card: var(--color-white);