fix(autoCombo): fallback to base model intelligence for -free alias models (#8601) (#8662)

When looking up models_dev_tier or capability scores for -free alias models (e.g. deepseek-v4-flash-free), strip the -free suffix to query the underlying model's intelligence data if direct lookup yields null.

Co-authored-by: Austin Liu <austinliu@Austins-MacBook-Air-3.local>
Co-authored-by: diegosouzapw <diegosouzapw@users.noreply.github.com>

tests/unit/autoCombo/free-alias-intelligence-8601.test.ts

@@ -0,0 +1,24 @@
+import { describe, it, expect } from "vitest";
+import {
+  getModelsDevTierFitness,
+  getTaskFitnessWithSource,
+} from "../../../open-sse/services/autoCombo/taskFitness.js";
+
+describe("models_dev_tier free-alias fallback (#8601)", () => {
+  it("should return fitness score for -free alias from models_dev_tier DB or capabilities fallback", () => {
+    // Standard model without free suffix should match or resolve
+    const baseScore = getModelsDevTierFitness("deepseek-v4-flash", "coding");
+    const freeScore = getModelsDevTierFitness("deepseek-v4-flash-free", "coding");
+
+    // If baseScore is resolved (or capability fallback works), freeScore should match baseScore
+    if (baseScore !== null) {
+      expect(freeScore).toBe(baseScore);
+    }
+  });
+
+  it("getTaskFitnessWithSource should fall back for models_dev_tier / arena_elo on -free models", () => {
+    const res = getTaskFitnessWithSource("deepseek-v4-flash-free", "coding");
+    expect(res).not.toBeNull();
+    expect(typeof res.score).toBe("number");
+  });
+});