feat(provider): add MiniMax M-series reasoning toggle

MiniMax models (id contains "minimax") were in the variants() exclusion
list, so M3 exposed no reasoning control on any route despite supporting
the Anthropic `thinking` field (type: adaptive | disabled).

Remove minimax from the exclusion list and add instant/thinking variants,
mirroring the glm/kimi/qwen toggle added in #8484:
- @ai-sdk/anthropic (direct provider): map to native
  thinking:{type:"disabled"} / thinking:{type:"adaptive"}
- @kilocode/kilo-gateway + @openrouter/ai-sdk-provider: reuse the
  reasoning:{enabled} shape, translated by kiloProviderOptions.

Replace the obsolete "minimax returns empty object" test with coverage
for the direct-anthropic and kilo-gateway routes.

packages/opencode/src/provider/transform.ts

@@ -650,7 +650,7 @@ export function variants(model: Provider.Model): Record<string, Record<string, a
     id.includes("deepseek-reasoner") ||
     id.includes("deepseek-r1") ||
     id.includes("deepseek-v3") ||
-    id.includes("minimax") ||
+    // id.includes("minimax") || // kilocode_change
     // id.includes("glm") || // kilocode_change
     // id.includes("kimi") || // kilocode_change
     // TODO: Remove this after models.dev data is fixed to use "kimi-k2.5" instead of "k2p5"
@@ -680,7 +680,7 @@ export function variants(model: Provider.Model): Record<string, Record<string, a
     case "@kilocode/kilo-gateway": // kilocode_change
     case "@openrouter/ai-sdk-provider":
       // kilocode_change start
-      if (id.includes("glm") || id.includes("kimi") || id.includes("qwen")) {
+      if (id.includes("glm") || id.includes("kimi") || id.includes("qwen") || id.includes("minimax")) {
         return {
           instant: { reasoning: { enabled: false } },
           thinking: { reasoning: { enabled: true } },
@@ -856,6 +856,14 @@ export function variants(model: Provider.Model): Record<string, Record<string, a
     // https://v5.ai-sdk.dev/providers/ai-sdk-providers/anthropic
     case "@ai-sdk/google-vertex/anthropic":
       // https://v5.ai-sdk.dev/providers/ai-sdk-providers/google-vertex#anthropic-provider
+      // kilocode_change start - MiniMax M-series toggles thinking on/off rather than exposing effort levels
+      if (id.includes("minimax")) {
+        return {
+          instant: { thinking: { type: "disabled" } },
+          thinking: { thinking: { type: "adaptive" } },
+        }
+      }
+      // kilocode_change end
       if (adaptiveEfforts) {
         let efforts = [...adaptiveEfforts]
         if (model.providerID === "github-copilot") {

packages/opencode/test/provider/transform.test.ts

@@ -2410,18 +2410,38 @@ describe("ProviderTransform.variants", () => {
     expect(result).toEqual({})
   })
 
-  test("minimax returns empty object", () => {
+  test("minimax direct anthropic provider returns instant/thinking toggle", () => {
     const model = createMockModel({
-      id: "minimax/minimax-model",
+      id: "minimax/MiniMax-M3",
       providerID: "minimax",
       api: {
-        id: "minimax-model",
-        url: "https://api.minimax.com",
-        npm: "@ai-sdk/openai-compatible",
+        id: "MiniMax-M3",
+        url: "https://api.minimax.io/anthropic/v1",
+        npm: "@ai-sdk/anthropic",
       },
     })
     const result = ProviderTransform.variants(model)
-    expect(result).toEqual({})
+    expect(result).toEqual({
+      instant: { thinking: { type: "disabled" } },
+      thinking: { thinking: { type: "adaptive" } },
+    })
+  })
+
+  test("minimax via kilo gateway returns instant/thinking toggle", () => {
+    const model = createMockModel({
+      id: "kilo/minimax/minimax-m3",
+      providerID: "kilo",
+      api: {
+        id: "minimax/minimax-m3",
+        url: "https://gateway.kilo.ai",
+        npm: "@kilocode/kilo-gateway",
+      },
+    })
+    const result = ProviderTransform.variants(model)
+    expect(result).toEqual({
+      instant: { reasoning: { enabled: false } },
+      thinking: { reasoning: { enabled: true } },
+    })
   })
 
   test("glm returns empty object", () => {