feat(ai): add Xiaomi MiMo provider (#4005)

* fix(ai): include minimax-cn in cross-provider-handoff matrix

* feat(ai): add Xiaomi MiMo provider

Adds Xiaomi MiMo as an openai-completions-compatible provider.

- packages/ai: register provider in types/KnownProvider, env-api-keys (XIAOMI_API_KEY), generate-models, models.generated.ts, overflow util, README, CHANGELOG
- packages/ai/test: extend stream, tokens, abort, empty, context-overflow, overflow, image-tool-result, tool-call-without-result, total-tokens, unicode-surrogate, cross-provider-handoff matrices with Xiaomi
- packages/coding-agent: default model (mimo-v2.5-pro), display name (Xiaomi MiMo), CLI env var docs, README, docs/providers.md

closes #3912

---------

Co-authored-by: Mario Zechner <badlogicgames@gmail.com>

packages/ai/test/total-tokens.test.ts

@@ -443,6 +443,29 @@ describe("totalTokens field", () => {
 		);
 	});
 
+	// =========================================================================
+	// Xiaomi MiMo
+	// =========================================================================
+
+	describe.skipIf(!process.env.XIAOMI_API_KEY)("Xiaomi MiMo", () => {
+		it(
+			"mimo-v2.5-pro - should return totalTokens equal to sum of components",
+			{ retry: 3, timeout: 60000 },
+			async () => {
+				const llm = getModel("xiaomi", "mimo-v2.5-pro");
+
+				console.log(`\nXiaomi MiMo / ${llm.id}:`);
+				const { first, second } = await testTotalTokensWithCache(llm, { apiKey: process.env.XIAOMI_API_KEY });
+
+				logUsage("First request", first);
+				logUsage("Second request", second);
+
+				assertTotalTokensEqualsComponents(first);
+				assertTotalTokensEqualsComponents(second);
+			},
+		);
+	});
+
 	// =========================================================================
 	// Kimi For Coding
 	// =========================================================================