refactor(explore): add minimax-m2.5-free as #2 fallback after grok-code-fast-1

src/shared/model-requirements.test.ts

@@ -64,23 +64,26 @@ describe("AGENT_MODEL_REQUIREMENTS", () => {
     const explore = AGENT_MODEL_REQUIREMENTS["explore"]
 
     // when - accessing explore requirement
-    // then - fallbackChain exists with grok-code-fast-1 as first entry, claude-haiku-4-5 as second
+    // then - fallbackChain exists with grok-code-fast-1 as first entry, minimax-m2.5-free as second
     expect(explore).toBeDefined()
     expect(explore.fallbackChain).toBeArray()
-    expect(explore.fallbackChain).toHaveLength(3)
+    expect(explore.fallbackChain).toHaveLength(4)
 
     const primary = explore.fallbackChain[0]
     expect(primary.providers).toContain("github-copilot")
     expect(primary.model).toBe("grok-code-fast-1")
 
     const secondary = explore.fallbackChain[1]
-    expect(secondary.providers).toContain("anthropic")
     expect(secondary.providers).toContain("opencode")
-    expect(secondary.model).toBe("claude-haiku-4-5")
+    expect(secondary.model).toBe("minimax-m2.5-free")
 
     const tertiary = explore.fallbackChain[2]
-    expect(tertiary.providers).toContain("opencode")
-    expect(tertiary.model).toBe("gpt-5-nano")
+    expect(tertiary.providers).toContain("anthropic")
+    expect(tertiary.model).toBe("claude-haiku-4-5")
+
+    const quaternary = explore.fallbackChain[3]
+    expect(quaternary.providers).toContain("opencode")
+    expect(quaternary.model).toBe("gpt-5-nano")
   })
 
   test("multimodal-looker has valid fallbackChain with gemini-3-flash as primary", () => {

src/shared/model-requirements.ts

@@ -46,6 +46,7 @@ export const AGENT_MODEL_REQUIREMENTS: Record<string, ModelRequirement> = {
   explore: {
     fallbackChain: [
       { providers: ["github-copilot"], model: "grok-code-fast-1" },
+      { providers: ["opencode"], model: "minimax-m2.5-free" },
       { providers: ["anthropic", "opencode"], model: "claude-haiku-4-5" },
       { providers: ["opencode"], model: "gpt-5-nano" },
     ],