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

lib/types/model-config.ts

@@ -52,7 +52,6 @@ export interface ProviderConfig {
     vertexApiKey?: string // Express Mode API key
 
     models: ModelConfig[]
-    validated?: boolean // Has API key been validated
 }
 
 // The complete multi-model configuration
@@ -60,9 +59,6 @@ export interface MultiModelConfig {
     version: 1
     providers: ProviderConfig[]
     selectedModelId?: string // Currently selected model's UUID
-    // Older versions saved here whether untested models were listed in the
-    // model picker; they always are now
-    showUnvalidatedModels?: boolean
 }
 
 // Flattened model for dropdown display
@@ -86,10 +82,6 @@ export interface FlattenedModel {
     source?: "user" | "server"
     // Whether this model is the server default (matches AI_MODEL env var)
     isDefault?: boolean
-    // Custom env var name(s) for server models
-    // Can be a single string or array of strings for load balancing
-    apiKeyEnv?: string | string[]
-    baseUrlEnv?: string
 }
 
 // Providers whose server credentials live in fixed env vars
@@ -557,7 +549,6 @@ export function createProviderConfig(provider: ProviderName): ProviderConfig {
         apiKey: "",
         baseUrl: PROVIDER_INFO[provider].defaultBaseUrl,
         models: [],
-        validated: false,
     }
 }