feat(ai): add Kimi For Coding provider support

- Add kimi-coding provider using Anthropic Messages API
- API endpoint: https://api.kimi.com/coding/v1
- Environment variable: KIMI_API_KEY
- Models: kimi-k2-thinking (text), k2p5 (text + image)
- Add context overflow detection pattern for Kimi errors
- Add tests for all standard test suites

packages/ai/test/stream.test.ts

@@ -862,6 +862,33 @@ describe("Generate E2E Tests", () => {
 		});
 	});
 
+	describe.skipIf(!process.env.KIMI_API_KEY)(
+		"Kimi For Coding Provider (kimi-k2-thinking via Anthropic Messages)",
+		() => {
+			const llm = getModel("kimi-coding", "kimi-k2-thinking");
+
+			it("should complete basic text generation", { retry: 3 }, async () => {
+				await basicTextGeneration(llm);
+			});
+
+			it("should handle tool calling", { retry: 3 }, async () => {
+				await handleToolCall(llm);
+			});
+
+			it("should handle streaming", { retry: 3 }, async () => {
+				await handleStreaming(llm);
+			});
+
+			it("should handle thinking mode", { retry: 3 }, async () => {
+				await handleThinking(llm, { thinkingEnabled: true, thinkingBudgetTokens: 2048 });
+			});
+
+			it("should handle multi-turn with thinking and tools", { retry: 3 }, async () => {
+				await multiTurn(llm, { thinkingEnabled: true, thinkingBudgetTokens: 2048 });
+			});
+		},
+	);
+
 	// =========================================================================
 	// OAuth-based providers (credentials from ~/.pi/agent/oauth.json)
 	// Tokens are resolved at module level (see oauthTokens above)