feat(ci): Renovate automated dependency updates (RECOMMENDATIONS #2)

Weekly Renovate run against this Gitea instance: grouped minor/patch PRs per
ecosystem, individually-reviewed majors (dashboard approval), immediate
security-alert PRs. All update PRs ride the existing required CI gates
(build/tests/gitleaks/vuln/live-db/format), so merging one is as safe as any
other PR.

ONE MANUAL STEP remains: create a Gitea PAT (repo rw, user r, issue rw, org r)
and add it as the RENOVATE_TOKEN Actions secret — the workflow fails fast with
instructions until then.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.gitea/workflows/renovate.yml

@@ -0,0 +1,35 @@
+name: Renovate
+
+# RECOMMENDATIONS #2: automated dependency-update PRs (NuGet, npm, Dockerfiles, Actions)
+# that ride the existing required CI gates. Runs weekly + on demand.
+#
+# ONE-TIME SETUP (manual): create a Gitea personal access token with scopes
+# repo (rw) + user (r) + issue (rw) + organization (r), and add it as the Actions
+# secret RENOVATE_TOKEN (repo Settings -> Actions -> Secrets). Without the secret this
+# workflow fails fast with a clear message. See https://docs.renovatebot.com/modules/platform/gitea/
+on:
+  schedule:
+    - cron: '30 4 * * 1'      # Mondays 04:30 UTC
+  workflow_dispatch: {}
+
+jobs:
+  renovate:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Require RENOVATE_TOKEN
+        run: |
+          if [ -z "${{ secrets.RENOVATE_TOKEN }}" ]; then
+            echo "RENOVATE_TOKEN secret is not set — see the comment at the top of this workflow." >&2
+            exit 1
+          fi
+      - name: Run Renovate
+        uses: https://github.com/renovatebot/github-action@v40.3.6
+        with:
+          token: ${{ secrets.RENOVATE_TOKEN }}
+        env:
+          RENOVATE_PLATFORM: gitea
+          RENOVATE_ENDPOINT: https://git.cesnimda.uk/api/v1
+          RENOVATE_REPOSITORIES: cesnimda/Inboxintel
+          RENOVATE_ONBOARDING: "false"
+          RENOVATE_REQUIRE_CONFIG: optional
+          LOG_LEVEL: info

renovate.json

@@ -0,0 +1,27 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": ["config:recommended"],
+  "timezone": "Europe/Berlin",
+  "schedule": ["before 6am on monday"],
+  "labels": ["dependencies"],
+  "prConcurrentLimit": 5,
+  "commitMessagePrefix": "chore(deps):",
+  "packageRules": [
+    {
+      "description": "Group safe minor+patch updates into one weekly PR per ecosystem",
+      "matchUpdateTypes": ["minor", "patch"],
+      "groupName": "{{manager}} minor & patch"
+    },
+    {
+      "description": "Major updates stay individual PRs for careful review",
+      "matchUpdateTypes": ["major"],
+      "dependencyDashboardApproval": true
+    }
+  ],
+  "vulnerabilityAlerts": {
+    "enabled": true,
+    "labels": ["security"],
+    "schedule": ["at any time"]
+  },
+  "ignorePaths": ["**/node_modules/**", "**/bin/**", "**/obj/**"]
+}