fix: update DeepSeek models context window to 128k

- Updated deepseek-chat and deepseek-reasoner models from 64k to 128k context window
- Updated corresponding test expectations
- Aligns with DeepSeek API documentation at https://api-docs.deepseek.com/quick_start/pricing/

Fixes #7268

Author: roomote

packages/types/src/providers/deepseek.ts

@@ -8,7 +8,7 @@ export const deepSeekDefaultModelId: DeepSeekModelId = "deepseek-chat"
 export const deepSeekModels = {
 	"deepseek-chat": {
 		maxTokens: 8192,
-		contextWindow: 64_000,
+		contextWindow: 128_000,
 		supportsImages: false,
 		supportsPromptCache: true,
 		inputPrice: 0.27, // $0.27 per million tokens (cache miss)
@@ -19,7 +19,7 @@ export const deepSeekModels = {
 	},
 	"deepseek-reasoner": {
 		maxTokens: 8192,
-		contextWindow: 64_000,
+		contextWindow: 128_000,
 		supportsImages: false,
 		supportsPromptCache: true,
 		inputPrice: 0.55, // $0.55 per million tokens (cache miss)

src/api/providers/__tests__/deepseek.spec.ts

@@ -155,7 +155,7 @@ describe("DeepSeekHandler", () => {
 			expect(model.id).toBe(mockOptions.apiModelId)
 			expect(model.info).toBeDefined()
 			expect(model.info.maxTokens).toBe(8192)
-			expect(model.info.contextWindow).toBe(64_000)
+			expect(model.info.contextWindow).toBe(128_000)
 			expect(model.info.supportsImages).toBe(false)
 			expect(model.info.supportsPromptCache).toBe(true) // Should be true now
 		})