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/.archived/calibration_backlog.yml

@@ -0,0 +1,80 @@
+name: Calibration Backlog (Registry Drift Watch)
+
+on:
+  schedule:
+    - cron: "15 2 * * 1-5"   # UTC 02:15 = KST 11:15, weekday backlog update
+  workflow_dispatch:
+
+jobs:
+  build-calibration-backlog:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout Code
+      run: |
+        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: Configure Runtime Paths
+      run: |
+        export PATH=/usr/local/bin:$PATH
+        echo "/usr/local/bin" >> $GITHUB_PATH
+        /usr/bin/python3 --version
+
+    - name: Setup Python Environment
+      run: |
+        VENV_BASE=/volume1/gitea/python_venv
+        REQ_HASH=$(md5sum tools/build_calibration_priority_v1.py 2>/dev/null | cut -d' ' -f1 || echo "calib-default")
+        VENV="$VENV_BASE/$REQ_HASH"
+
+        if [ ! -f "$VENV/bin/python" ]; then
+          mkdir -p "$VENV_BASE"
+          /usr/bin/python3 -m venv "$VENV"
+          if [ ! -f "$VENV/bin/pip" ]; then
+            curl -sS https://bootstrap.pypa.io/pip/3.8/get-pip.py -o get-pip.py
+            "$VENV/bin/python" get-pip.py --quiet
+            rm get-pip.py
+          fi
+          "$VENV/bin/pip" install --upgrade pip --quiet
+          "$VENV/bin/pip" install pyyaml --quiet
+        fi
+        echo "$VENV/bin" >> $GITHUB_PATH
+
+    - name: Validate Calibration Registry
+      run: python3 tools/validate_calibration_registry_v1.py
+
+    - name: Build Calibration Priority Backlog
+      run: python3 tools/build_calibration_priority_v1.py
+
+    - name: Build Calibration Change Ledger
+      run: python3 tools/build_calibration_change_ledger_v4.py
+
+    - name: Build Calibration Review Report
+      run: python3 tools/build_calibration_review_report_v1.py
+
+    - name: Build Calibration Approval List
+      run: python3 tools/build_calibration_approval_list_v1.py
+
+    - name: Build Calibration Decision Draft
+      run: python3 tools/build_calibration_decision_draft_v1.py
+
+    - name: Validate Calibration Change Ledger
+      run: python3 tools/validate_calibration_change_ledger_v1.py
+
+    - name: Summarize Backlog
+      if: always()
+      run: |
+        STATUS="${{ job.status }}"
+        echo "=== Calibration Backlog Result ==="
+        echo "status: $STATUS"
+        echo "priority: Temp/calibration_priority_v1.json"
+        echo "ledger: Temp/calibration_change_ledger_v4.json"
+        echo "review: Temp/calibration_review_report_v1.md"
+        echo "approval: Temp/calibration_approval_list_v1.md"
+        echo "decision: Temp/calibration_decision_draft_v1.md"