test(model-pricing): add cache pricing coverage for Opus 4.7

Mirrors the existing `claude-opus-4-6` cache pricing test for both
`claude-opus-4-7` and `claude-opus-4-7-thinking` to explicitly
validate cache creation/read rates in end-to-end cost calculation.

Addresses PResto atrvd/ccs#8 issue #6 (suggestion).

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tests/unit/model-pricing.test.ts

@@ -236,6 +236,28 @@ describe('model-pricing', () => {
       const cost = calculateCost(usage, 'claude-opus-4-6');
       expect(cost).toBe(36.75); // 5 + 25 + 6.25 + 0.5
     });
+
+    it('should calculate Claude Opus 4.7 cost including cache token rates', () => {
+      const usage: TokenUsage = {
+        inputTokens: 1_000_000,
+        outputTokens: 1_000_000,
+        cacheCreationTokens: 1_000_000,
+        cacheReadTokens: 1_000_000,
+      };
+      const cost = calculateCost(usage, 'claude-opus-4-7');
+      expect(cost).toBe(36.75); // 5 + 25 + 6.25 + 0.5
+    });
+
+    it('should calculate Claude Opus 4.7 Thinking cost including cache token rates', () => {
+      const usage: TokenUsage = {
+        inputTokens: 1_000_000,
+        outputTokens: 1_000_000,
+        cacheCreationTokens: 1_000_000,
+        cacheReadTokens: 1_000_000,
+      };
+      const cost = calculateCost(usage, 'claude-opus-4-7-thinking');
+      expect(cost).toBe(36.75); // 5 + 25 + 6.25 + 0.5
+    });
   });
 
   describe('getKnownModels', () => {