refactor(settings): remove wrapper layers, dead props and unused dictionary keys

- components/model-selector.tsx uses Dialog, Command and Tooltip
  directly; delete components/ai-elements/model-selector.tsx and
  components/button-with-tooltip.tsx; one renderGroups for both lists;
  no "Server · " prefix round trip
- components/ui: drop CommandDialog, CommandShortcut and six unused
  shadcn exports
- model-config-dialog: no type-to-confirm on provider delete;
  provider-credentials-fields: drop footer and bedrockApiKey
- hooks/use-model-config.ts and lib/types/model-config.ts: remove the
  2025-12 single-provider migration, resetConfig, selectedModel and
  fields nothing reads
- components/chat/TemplateFormDialog.tsx replaces the create and edit
  dialogs; TemplatePanel drops the setInput fallback, the
  templatesChanged listener, dictionary fallbacks and formatLastUsed;
  lib/template-storage.ts drops getTemplate, clickCount and indexes
- reasoning.tsx becomes one component; shimmer uses a CSS keyframe
  (motion and @radix-ui/react-use-controllable-state removed)
- error-toast.tsx deleted in favour of toast.error; ValidationCard
  drops the idle status; dev-xml-simulator uses English literals
- admin: no enum setting type, shared types from lib/admin
  (AdminProviderInput stays exported for that), ENABLE_HISTORY_XML_REPLACE
  entry removed
- app/globals.css: drop check-pop, --ease-spring, --duration-normal
  and the shadow aliases
- dictionaries: 81 unused keys removed from all four languages

app/globals.css

@@ -98,9 +98,7 @@
     --shadow-pop:
         0 1px 2px rgb(20 24 29 / 0.06), 0 18px 48px -12px rgb(20 24 29 / 0.22);
 
-    --duration-normal: 200ms;
     --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
-    --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
 }
 
 /*
@@ -241,13 +239,6 @@
     .shadow-pop {
         box-shadow: var(--shadow-pop);
     }
-    /* Older names kept for components that still use them */
-    .shadow-soft {
-        box-shadow: var(--shadow-float);
-    }
-    .shadow-dialog {
-        box-shadow: var(--shadow-pop);
-    }
 }
 
 @keyframes fadeIn {
@@ -284,17 +275,13 @@
     }
 }
 
-@keyframes check-pop {
-    0% {
-        transform: scale(0.8);
-        opacity: 0;
+/* A highlight sweeps across "Thinking..." text (Shimmer) */
+@keyframes shimmer {
+    from {
+        background-position: 100% center;
     }
-    50% {
-        transform: scale(1.1);
-    }
-    100% {
-        transform: scale(1);
-        opacity: 1;
+    to {
+        background-position: 0% center;
     }
 }
 
@@ -307,15 +294,15 @@
 .animate-panel-in {
     animation: panelIn 0.32s var(--ease-out) both;
 }
-.animate-check-pop {
-    animation: check-pop 0.25s var(--ease-spring) forwards;
+.animate-shimmer {
+    animation: shimmer var(--shimmer-duration, 2s) linear infinite;
 }
 
 @media (prefers-reduced-motion: reduce) {
     .animate-fade-in,
     .animate-message-in,
     .animate-panel-in,
-    .animate-check-pop {
+    .animate-shimmer {
         animation: none;
     }
 }