chore: Archive 7 unused workflows and consolidate to SSOT pipeline

Reorganized .gitea/workflows/ to reduce duplication and noise:
- Archived 7 unnecessary workflows to .archived/ subdirectory:
  - auto_backup_schedule.yml
  - backup.yml
  - calibration_backlog.yml
  - kis_data_collection.yml
  - qualitative_sell_strategy.yml
  - snapshot_admin.yml
  - wbs_9_3_null_policy_ci_gate.yml

Active workflows (5 total):
- merge-to-main.yml (SSOT 5-stage pipeline)
- ci.yml (PR validation)
- deploy-prod.yml (manual deployment)
- fast-validation.yml (PR fast checks)
- _common/build-and-test.yml (reusable component)

Rationale: Phase 2 deployment infrastructure is complete. Legacy workflows
are no longer needed, reducing CI/CD maintenance burden and improving clarity.
Archived workflows remain available for reference if rollback is needed.

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

.gitea/workflows/snapshot_admin.yml

@@ -1,111 +0,0 @@
-name: Snapshot Admin Web Validation
-
-on:
-  workflow_dispatch:
-  push:
-    paths:
-      - "src/quant_engine/snapshot_admin_server_v1.py"
-      - "src/quant_engine/snapshot_admin_store_v1.py"
-      - "tools/run_snapshot_admin_server_v1.py"
-      - "tools/validate_snapshot_admin_workflow_v1.py"
-      - "tools/validate_snapshot_admin_web_v1.py"
-      - "spec/15_account_snapshot_contract.yaml"
-      - "spec/18_settings_contract.yaml"
-      - "GatherTradingData.json"
-
-jobs:
-  # Push-only smoke gate: no deployment, no web UI smoke, no long-running side effects.
-  validate-snapshot-admin-smoke:
-    if: github.event_name == 'push'
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout Code
-        run: |
-          echo "[smoke] push-only snapshot admin workflow validation"
-          if [ -d .git ]; then
-            git remote set-url origin http://x-access-token:${{ secrets.GITHUB_TOKEN }}@192.168.123.100:8418/KimJaeHyun/myfinance.git
-          else
-            git init
-            git remote add origin http://x-access-token:${{ secrets.GITHUB_TOKEN }}@192.168.123.100:8418/KimJaeHyun/myfinance.git
-          fi
-          git fetch origin main --depth=1
-          git reset --hard FETCH_HEAD
-
-      - name: Setup Python Environment
-        run: |
-          echo "[smoke] prepare python venv"
-          VENV_BASE=/volume1/gitea/python_venv
-          REQ_HASH=$(md5sum tools/validate_snapshot_admin_workflow_v1.py 2>/dev/null | cut -d' ' -f1 || echo "snapshot-admin-default")
-          VENV="$VENV_BASE/$REQ_HASH"
-          if [ ! -f "$VENV/bin/python" ]; then
-            mkdir -p "$VENV_BASE"
-            /usr/bin/python3 -m venv "$VENV"
-            "$VENV/bin/pip" install --upgrade pip --quiet
-          fi
-          "$VENV/bin/pip" install pyyaml --quiet
-          echo "$VENV/bin" >> $GITHUB_PATH
-
-      - name: Validate Snapshot Admin Workflow
-        run: |
-          echo "[smoke] validate workflow only (no web UI, no deploy)"
-          python3 tools/validate_snapshot_admin_workflow_v1.py
-
-      - name: Validate DB First Pipeline
-        run: |
-          echo "[smoke] validate DB-first pipeline contract"
-          python3 tools/validate_db_first_pipeline_v1.py
-
-  # Manual dispatch gate: full workflow + web UI validation only.
-  validate-snapshot-admin-full:
-    if: github.event_name == 'workflow_dispatch'
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout Code
-        run: |
-          echo "[full] workflow_dispatch snapshot admin validation"
-          if [ -d .git ]; then
-            git remote set-url origin http://x-access-token:${{ secrets.GITHUB_TOKEN }}@192.168.123.100:8418/KimJaeHyun/myfinance.git
-          else
-            git init
-            git remote add origin http://x-access-token:${{ secrets.GITHUB_TOKEN }}@192.168.123.100:8418/KimJaeHyun/myfinance.git
-          fi
-          git fetch origin main --depth=1
-          git reset --hard FETCH_HEAD
-
-      - name: Setup Python Environment
-        run: |
-          echo "[full] prepare python venv"
-          VENV_BASE=/volume1/gitea/python_venv
-          REQ_HASH=$(md5sum tools/validate_snapshot_admin_workflow_v1.py 2>/dev/null | cut -d' ' -f1 || echo "snapshot-admin-default")
-          VENV="$VENV_BASE/$REQ_HASH"
-          if [ ! -f "$VENV/bin/python" ]; then
-            mkdir -p "$VENV_BASE"
-            /usr/bin/python3 -m venv "$VENV"
-            "$VENV/bin/pip" install --upgrade pip --quiet
-          fi
-          "$VENV/bin/pip" install pyyaml --quiet
-          echo "$VENV/bin" >> $GITHUB_PATH
-
-      - name: Validate Snapshot Admin Workflow
-        run: |
-          echo "[full] validate workflow"
-          python3 tools/validate_snapshot_admin_workflow_v1.py
-
-      - name: Validate DB First Pipeline
-        run: |
-          echo "[full] validate DB-first pipeline contract"
-          python3 tools/validate_db_first_pipeline_v1.py
-
-      - name: Validate Snapshot Admin Web UI
-        run: |
-          echo "[full] validate web ui"
-          python3 tools/validate_snapshot_admin_web_v1.py
-
-      - name: Notify Run Result
-        if: always()
-        run: |
-          STATUS="${{ job.status }}"
-          echo "=== Snapshot Admin Full Validation ==="
-          echo "status: $STATUS"
-          echo "workflow validation: Temp/snapshot_admin_workflow_v1.json"
-          echo "web validation: Temp/snapshot_admin_web_validation_v1.json"