chore: remove dead code and consolidate duplicate types (#555)

- Delete unused files: lib/ai-config.ts, components/ui/card.tsx, lib/token-counter.ts
- Remove js-tiktoken dependency (only used by deleted token-counter.ts)
- Consolidate ProviderName type: add "ollama" to model-config.ts, import in ai-providers.ts
- Consolidate DiagramOperation type: keep in chat/types.ts, import in utils.ts and hook

lib/types/model-config.ts

@@ -6,6 +6,7 @@ export type ProviderName =
     | "google"
     | "azure"
     | "bedrock"
+    | "ollama"
     | "openrouter"
     | "deepseek"
     | "siliconflow"
@@ -76,6 +77,10 @@ export const PROVIDER_INFO: Record<
     google: { label: "Google" },
     azure: { label: "Azure OpenAI" },
     bedrock: { label: "Amazon Bedrock" },
+    ollama: {
+        label: "Ollama",
+        defaultBaseUrl: "http://localhost:11434",
+    },
     openrouter: { label: "OpenRouter" },
     deepseek: { label: "DeepSeek" },
     siliconflow: {
@@ -99,7 +104,7 @@ export const PROVIDER_INFO: Record<
 }
 
 // Suggested models per provider for quick add
-export const SUGGESTED_MODELS: Record<ProviderName, string[]> = {
+export const SUGGESTED_MODELS: Partial<Record<ProviderName, string[]>> = {
     openai: [
         "gpt-5.2-pro",
         "gpt-5.2-chat-latest",