ci: add dependency-audit and changelog Gitea workflows

- audit.yml: weekly `dotnet list package --vulnerable` scan that files an issue on findings
- changelog.yml: generate a changelog on `v*` tag pushes

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.gitea/workflows/audit.yml

@@ -0,0 +1,101 @@
+name: Dependency Audit
+
+on:
+  schedule:
+    - cron: '0 6 * * 1'   # Mondays 06:00 UTC
+  workflow_dispatch: {}
+
+jobs:
+  audit:
+    runs-on: ubuntu-latest
+    env:
+      DOTNET_ROOT: /home/mika/.dotnet
+      GITEA_API: https://git.kuns.dev/api/v1
+      REPO: releases/ClaudeDo
+      ISSUE_TITLE: 'Dependency audit: vulnerable packages detected'
+    steps:
+      - name: Checkout main
+        env:
+          TOKEN: ${{ secrets.GITEA_TOKEN }}
+        run: |
+          set -euo pipefail
+          git clone --depth 1 --branch main \
+            "https://oauth2:${TOKEN}@git.kuns.dev/${REPO}.git" src
+
+      - name: Scan for vulnerable / outdated packages
+        run: |
+          set -euo pipefail
+          export PATH="$DOTNET_ROOT:$PATH"
+          cd src
+
+          : > audit.log
+          : > vuln.md
+          found=0
+
+          # .slnx tooling needs .NET 9; iterate per-project to stay on .NET 8.
+          while IFS= read -r proj; do
+            echo "==== $proj ====" | tee -a audit.log
+            dotnet restore "$proj" >/dev/null
+
+            vuln="$(dotnet list "$proj" package --vulnerable --include-transitive 2>&1)"
+            echo "$vuln" | tee -a audit.log
+            if echo "$vuln" | grep -qi "has the following vulnerable"; then
+              found=1
+              {
+                printf '#### `%s`\n\n```\n' "$proj"
+                echo "$vuln"
+                printf '```\n\n'
+              } >> vuln.md
+            fi
+
+            # Outdated is informational only — never fails the run.
+            dotnet list "$proj" package --outdated 2>&1 | tee -a audit.log || true
+            echo "" | tee -a audit.log
+          done < <(find . -name '*.csproj' | sort)
+
+          if [ "$found" -ne 0 ]; then
+            echo "::error::Vulnerable packages detected — see log above." >&2
+            exit 1
+          fi
+          echo "No vulnerable packages found."
+
+      - name: Report vulnerabilities to a Gitea issue
+        if: failure()
+        env:
+          TOKEN:  ${{ secrets.GITEA_TOKEN }}
+          RUN_URL: ${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}
+        run: |
+          set -euo pipefail
+          cd src
+
+          if [ -s vuln.md ]; then
+            DETAILS="$(cat vuln.md)"
+          else
+            DETAILS="The audit job failed before producing findings — check the run log."
+          fi
+          BODY="$(printf 'Automated weekly dependency audit found vulnerable packages.\n\n%s\n\n[View workflow run](%s)' \
+            "$DETAILS" "$RUN_URL")"
+
+          # Reuse an existing open issue if one is already tracking this.
+          EXISTING="$(curl -sS \
+            -H "Authorization: token ${TOKEN}" \
+            "${GITEA_API}/repos/${REPO}/issues?state=open&type=issues&limit=50" \
+            | jq -r --arg t "$ISSUE_TITLE" '.[] | select(.title==$t) | .number' | head -n1)"
+
+          if [ -n "$EXISTING" ]; then
+            echo "Commenting on existing issue #$EXISTING"
+            jq -n --arg body "$BODY" '{body:$body}' \
+              | curl -sS --fail-with-body -X POST \
+                  -H "Authorization: token ${TOKEN}" \
+                  -H "Content-Type: application/json" \
+                  -d @- \
+                  "${GITEA_API}/repos/${REPO}/issues/${EXISTING}/comments" >/dev/null
+          else
+            echo "Creating new issue"
+            jq -n --arg title "$ISSUE_TITLE" --arg body "$BODY" '{title:$title, body:$body}' \
+              | curl -sS --fail-with-body -X POST \
+                  -H "Authorization: token ${TOKEN}" \
+                  -H "Content-Type: application/json" \
+                  -d @- \
+                  "${GITEA_API}/repos/${REPO}/issues" >/dev/null
+          fi