chore(models): finish the opus-5 replacement — no stale opus-4 fixtures remain

Every fixture, comment example, and panel mock that presented an Opus 4.x
id as current now carries claude-opus-5 (or the current sonnet/haiku ids in
the panel usage mocks). The only deliberate claude-opus-4 survivors are the
pricing-table fragment and its tests — they price the historical usage rows,
which would otherwise re-read as $0.

tests/integration/test_optimal_routes.py

@@ -940,7 +940,7 @@ async def test_review_code(optimal_client: AsyncClient) -> None:
 async def test_estimate_tokens(optimal_client: AsyncClient) -> None:
     response = await optimal_client.post(
         "/api/optimal/tokens/estimate",
-        json={"content": "Hello world", "model": "claude-opus-4-7"},
+        json={"content": "Hello world", "model": "claude-opus-5"},
         headers=_HDR,
     )
     assert response.status_code == HTTPStatus.OK

tests/unit/billing/test_pricing.py

@@ -562,15 +562,7 @@ class TestProviderAwareness:
         assert cost == _ZERO_COST
 
     def test_is_anthropic_model_true_for_claude_names(self) -> None:
-        for name in (
-            "claude-opus-4-6",
-            "claude-opus-4-8",
-            "claude-opus-5",
-            "claude-fable-5",
-            "opus",
-            "sonnet",
-            "haiku",
-        ):
+        for name in ("claude-opus-5", "claude-fable-5", "opus", "sonnet", "haiku"):
             assert _is_anthropic_model(name) is True, name
 
     def test_is_anthropic_model_false_for_non_claude_names(self) -> None:
@@ -629,7 +621,7 @@ class TestCostResult:
         assert result.is_anthropic is False
 
     def test_calculate_cost_matches_structured_cost_usd(self) -> None:
-        model = "claude-opus-4-6"
+        model = "claude-opus-5"
         assert (
             calculate_cost(model, tokens_input=_M, tokens_output=_M)
             == calculate_cost_result(model, tokens_input=_M, tokens_output=_M).cost_usd

tests/unit/runtime/test_spawn_manifest.py

@@ -104,7 +104,7 @@ class TestWriteManifest:
                 role="developer",
                 team="backend",
                 workspace_path=tmp_path,
-                agent_model="claude-opus-4-7",
+                agent_model="claude-opus-5",
             )
         )
         manifest_path = tmp_path / "tool-manifest.json"

tests/unit/services/test_usage.py

@@ -629,7 +629,7 @@ class TestGetByModel:
                 cost_usd=0.02,
             ),
             _make_row(
-                model="claude-opus-4-5",
+                model="claude-opus-5",
                 tokens_input=100,
                 tokens_output=100,
                 tokens_cache_read=0,