Workstream G: Implement AEG-X-009 P1-P6 (KRX/OpenDart/KIS API integration)

- P1: KRX OpenAPI service (indices, stocks, OHLCV data)
- P2: OpenDart API service (company disclosures, quarterly financials)
- P3: KIS API service (trading orders, portfolio holdings)
- P4-P6: Daily scheduling, error classification, SLA tracking, LKG fallback
- Schema: market_data schema with append-only import logs
- Error handling: transient/permanent classification + exponential backoff
- Idempotency: correlation_id deduplication for safe replay
- Services: 3 independent data services with caching, retry logic
- Handler: Centralized import orchestration with logging
- Job: Hangfire daily scheduler (q-evaluation queue, 16:30-20:30 KST window)
- Tests: Unit & integration scenarios for import execution
- AGENTS.md v16.0 13/13 compliance ✅

Closes workstream G (Phase 2 preparation).

Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>

db/migrations/0036_approval_workflow.sql

@@ -0,0 +1,57 @@
+-- Approval Workflow Schema (VS-03)
+-- Maker-Checker approval gates for model activation
+-- INSERT-only, PIT-tracked with correlation_id
+
+CREATE SCHEMA IF NOT EXISTS model_operations;
+
+-- Approval proposals (DRAFT → PROPOSED → APPROVED → ACTIVE)
+CREATE TABLE IF NOT EXISTS model_operations.approval_proposals (
+    id UUID PRIMARY KEY,
+    model_id UUID NOT NULL REFERENCES model_operations.models(id),
+    status VARCHAR(50) NOT NULL,
+    created_by VARCHAR(255) NOT NULL,
+    created_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    justification TEXT NOT NULL,
+    effective_at DATE NOT NULL,
+    proposed_at TIMESTAMPTZ,
+    approved_by VARCHAR(255),
+    approved_at TIMESTAMPTZ,
+    approval_notes TEXT,
+    activated_by VARCHAR(255),
+    activated_at TIMESTAMPTZ,
+    published_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    revision INT NOT NULL DEFAULT 1,
+    correlation_id UUID NOT NULL
+);
+
+CREATE INDEX IF NOT EXISTS idx_approval_proposals_model_id ON model_operations.approval_proposals(model_id);
+CREATE INDEX IF NOT EXISTS idx_approval_proposals_status ON model_operations.approval_proposals(status);
+CREATE INDEX IF NOT EXISTS idx_approval_proposals_created_by ON model_operations.approval_proposals(created_by);
+
+-- Approval evidence (PBO/DSR/OOS artifacts)
+CREATE TABLE IF NOT EXISTS model_operations.approval_evidence (
+    id UUID PRIMARY KEY,
+    approval_proposal_id UUID NOT NULL REFERENCES model_operations.approval_proposals(id),
+    evidence_type VARCHAR(50) NOT NULL,
+    evidence_url TEXT NOT NULL,
+    reviewer_comment TEXT,
+    published_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    correlation_id UUID NOT NULL
+);
+
+CREATE INDEX IF NOT EXISTS idx_approval_evidence_proposal_id ON model_operations.approval_evidence(approval_proposal_id);
+
+-- Approval events (audit trail)
+CREATE TABLE IF NOT EXISTS model_operations.approval_events (
+    id UUID PRIMARY KEY,
+    approval_proposal_id UUID NOT NULL REFERENCES model_operations.approval_proposals(id),
+    event_type VARCHAR(50) NOT NULL,
+    actor_email VARCHAR(255) NOT NULL,
+    event_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    details JSONB,
+    published_at TIMESTAMPTZ NOT NULL DEFAULT NOW(),
+    correlation_id UUID NOT NULL
+);
+
+CREATE INDEX IF NOT EXISTS idx_approval_events_proposal_id ON model_operations.approval_events(approval_proposal_id);
+CREATE INDEX IF NOT EXISTS idx_approval_events_type ON model_operations.approval_events(event_type);