test(阶段策略): 锁定 Host 注入协议与 Prompt 边界

验证公共 Planner Prompt 不包含 Phase2 边界，Phase1 RunConfig 带受保护 phase，Phase2 策略包含写作用域、Structure 引用、adoption 完整分区和单 Compose Portfolio 规则。

script_build_host/tests/test_mission_factory.py

@@ -1,6 +1,7 @@
 import json
 from datetime import UTC, datetime
 
+from script_build_host.agents.prompts import PARAGRAPH_WORKER_PROMPT, PLANNER_PROMPT
 from script_build_host.application.mission_factory import ScriptMissionFactory
 from script_build_host.domain.input_snapshot import ScriptBuildInputSnapshotV1
 from script_build_host.domain.records import MissionBinding
@@ -64,11 +65,33 @@ def test_factory_reads_nested_real_topic_and_does_not_double_prefix_digest() ->
     assert "workflow" not in str(spec).lower()
     message = json.loads(factory.build_planner_message(_binding(), _snapshot()))
     assert message["input_sha256"] == "sha256:" + "b" * 64
+    assert "Retrieval children under that Direction" in message["instruction"]
+    assert "exact reason PHASE_ONE_CAPABILITY_BOUNDARY" in message["instruction"]
     config = factory.build_run_config(_binding(), _snapshot())
     assert config.agent_type == "script_planner"
     assert config.model == "planner-model"
     assert config.temperature == 0.1
     assert config.max_iterations == 42
     assert config.new_trace_id == "root"
+    assert config.context["phase"] == 1
     assert config.enable_memory is False
     assert config.enable_research_flow is False
+
+
+def test_common_planner_prompt_does_not_leak_phase_two_boundary() -> None:
+    factory = ScriptMissionFactory()
+    assert "PHASE_TWO_CANDIDATE_PORTFOLIO_READY" not in PLANNER_PROMPT
+    assert "using the returned Direction Task ID as `parent_task_id`" in PLANNER_PROMPT
+    assert "`PHASE_ONE_CAPABILITY_BOUNDARY` with no additional text" in PLANNER_PROMPT
+    phase_two = factory.build_phase_two_policy(_snapshot())
+    assert "PHASE_TWO_CANDIDATE_PORTFOLIO_READY" in phase_two
+    assert "CandidatePortfolio and Compose must use the exact parent" in phase_two
+    assert "script-build://writes/paragraphs/<stable-selector>" in phase_two
+    assert "script-build://writes/elements/<stable-selector>" in phase_two
+    assert "Never copy scope_ref into write_scope" in phase_two
+    assert "whole Structure accepted_decision_ref" in phase_two
+    assert "whole artifact_ref unchanged into base_artifact_ref" in phase_two
+    assert "must also include and adopt its covering" in phase_two
+    assert "must partition that complete candidate list" in phase_two
+    assert "candidate_decision_ids, adopted_decision_ids, and compose_order" in phase_two
+    assert "derive a strategy reference" in PARAGRAPH_WORKER_PROMPT