feat: complete dcy-015 monthly settlement dashboard

Merge dcy-015 monthly settlement dashboard delivery after local and GitHub Actions verification.

docs/srs/Interface/req-023_monthly-settlement-dashboard-shell-kpi-cashflow-budget.md

@@ -1,6 +1,6 @@
 # REQ-023 Monthly settlement dashboard shell, KPI, cashflow, and budget sections
 
-- Status: Approved
+- Status: Implemented
 - Type: Interface
 - Priority: High
 - Owner: 렛저장인
@@ -8,6 +8,7 @@
 - Depends On: REQ-022
 - Created At (KST): 2026-07-11 20:56 KST
 - Approved At: 2026-07-12 09:01 KST
+- Implemented At (KST): 2026-07-12 12:24 KST
 
 ## 1. Intent
 
@@ -41,3 +42,10 @@ Add the visible Streamlit `월정산` page shell and implement the first user-fa
 ## 5. Notes
 
 This slice intentionally stops before operational blocker/import/asset sections to keep the first UI delivery small and verifiable.
+
+## Implementation Evidence
+
+- Batch: `BAT-018`
+- QC verdict: `.stagepilot/delivery/dcy-015_monthly-settlement/bat-018-qc-verdict-03.md`
+- Validation: independent QC rerun confirmed `ruff check .` and `pytest -q tests/test_dashboard_app.py` pass.
+- Scope note: REQ-024 blocker/import/account/asset sections and REQ-025 evidence/next-action hardening remain separate approved follow-on slices.