feat(gas-thin-adapter): Phase 2 Extract — 23개 forbidden 함수 Python 매핑 + 3개 stub

GAS_THIN_ADAPTER_POLICY_V1 Phase 2 완료:
- tools/gas_thin_adapter_phase2_extract.py: 23개 forbidden GAS 함수 → Python canonical 매핑 생성
  (Temp/gas_python_migration_map_v1.json 출력)
- tools/gas_thin_adapter_stubs_v1.py: NEEDS_STUB 3개 stub 신규 작성
  runRouteFlow_, calcExportGate_, buildWatchLedger_
- spec/39: extract phase IN_PROGRESS, extract_result 블록 추가
  (mapped=20, needs_stub=3, readiness=87.0%)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

spec/39_gas_thin_adapter_policy.yaml

@@ -32,8 +32,30 @@ migration_plan:
       target: Temp/gas_business_logic_audit_v1.json
       action: 분류된 GAS 함수 목록을 확정한다.
     - phase: extract
+      status: IN_PROGRESS
       target: tools/
       action: business_logic 함수를 Python compiler/stub layer로 이전한다.
+      extract_result:
+        tool: tools/gas_thin_adapter_phase2_extract.py
+        output: Temp/gas_python_migration_map_v1.json
+        stubs_file: tools/gas_thin_adapter_stubs_v1.py
+        total_forbidden: 23
+        mapped_count: 20
+        needs_stub_count: 3
+        extraction_readiness_pct: 87.0
+        needs_stub:
+          - gas_function: runRouteFlow_
+            gas_file: gdf_03_portfolio_gates.gs
+            responsibility: [stop_loss]
+            stub: stub_run_route_flow
+          - gas_function: calcExportGate_
+            gas_file: gdf_04_execution_quality.gs
+            responsibility: [unknown]
+            stub: stub_calc_export_gate
+          - gas_function: buildWatchLedger_
+            gas_file: gdf_04_execution_quality.gs
+            responsibility: [stop_loss, take_profit]
+            stub: stub_build_watch_ledger
     - phase: thin_adapter
       target: gas_*.gs
       action: collect/normalize/export/display만 남기고 나머지를 호출 위임으로 전환한다.