chore(models): upgrade the opus alias to claude-opus-4-8

MODEL_MAP["opus"] moves off claude-opus-4-6 to the newest Opus tier at the
same price; pricing already matched via the claude-opus-4 fragment, and a
new test_opus_is_priced guard keeps the alias priced. Fixtures, panel
mocks, and docs follow.

tests/unit/runtime/test_intake_spawn.py

@@ -56,7 +56,7 @@ def _spec(**overrides: Any) -> _IntakeRunSpec:
         },
         "session_id": "sess-abc",
         "cwd": "/data/workspaces/roboco/board/intake-1",
-        "cli_model": "claude-opus-4-6",
+        "cli_model": "claude-opus-4-8",
         "api_url": "http://roboco-orchestrator:8000",
         "provider_base_url": None,
         "provider_auth_token": None,
@@ -108,7 +108,7 @@ class TestBuildIntakeRunCmd:
         assert "ROBOCO_WORKSPACE=/data/workspaces/roboco/board/intake-1" in cmd
         assert "ROBOCO_API_URL=http://roboco-orchestrator:8000" in cmd
         assert "ROBOCO_AGENT_ID=intake-1" in cmd
-        assert "CLAUDE_CODE_SUBAGENT_MODEL=claude-opus-4-6" in cmd
+        assert "CLAUDE_CODE_SUBAGENT_MODEL=claude-opus-4-8" in cmd
 
     def test_mounts_prompt_and_workspaces(self) -> None:
         cmd = AgentOrchestrator._build_intake_run_cmd(_spec())

tests/unit/runtime/test_orchestrator_manifest.py

@@ -99,7 +99,7 @@ class TestBuildManifestForAgent:
             mock_settings.manifest_host_dir = str(tmp_path)
             mock_settings.workspaces_root = str(tmp_path / "workspaces")
 
-            result = _build_manifest_for_agent("be-dev-1", "claude-opus-4-6")
+            result = _build_manifest_for_agent("be-dev-1", "claude-opus-4-8")
 
         assert result is not None
         data = json.loads(result.read_text())

tests/unit/runtime/test_spawn_manifest.py

@@ -87,7 +87,7 @@ class TestBuildForRole:
                 role=role,
                 team="board",
                 workspace_path=Path("/tmp/x"),
-                agent_model="claude-opus-4-6",
+                agent_model="claude-opus-4-8",
             )
         )
         assert "read_messages" in m.do_tools