ci: Tidy CI pipeline for readability and performance

Pipeline Modernisation:
- Update prefligit to prek (same project, renamed to avoid
  typosquatting)
- Replace custom rust-toolchain action with direct uvx rustup
  invocation
- Remove dependency on install scripts in favour of uvx tool
  execution
- Make sccache conditional on GH_APP_ID and GH_APP_PRIVATE_KEY
  availability

Workflow Restructuring:
- Rename workflows for improved clarity:
  * rust-checks.yml → ci-checks.yml (consolidates Rust + prek)
  * element.yml → deploy-element.yml
  * documentation.yml → deploy-docs.yml
  * release-image.yml → release-builds.yml (Docker + binaries)
  * mirror-images.yml → docker-mirror.yml
- Delete obsolete prefligit-checks.yml (merged into ci-checks.yml)
- Combine format and prek checks into single fast-checks job

Cache Strategy Improvements (release-builds.yml):
- Add restore-keys to Rust registry and cargo target caches
- Include Cargo.toml files in cargo-target cache key
- Consolidate separate apt-cache and apt-lib steps into single step
- Version APT cache with Dockerfile hash instead of static keys
- Add platform-specific Docker buildcache tags
- Simplify Rust registry paths (remove checkouts/src subdirs)

CI Execution Improvements:
- Add uv cache for faster uvx tool invocations (prek, rustup)
- Enable concurrency control with cancel-in-progress
- Fix BOM handling in pre-commit

Dependency Management:
- Add renovate.yml workflow for scheduled dependency checking
- Configure renovate.json to monitor .forgejo/ and .github/ dirs
- Group non-major GitHub Actions updates into single PRs
- Set PR limits: 3 concurrent, 2 per hour

.forgejo/workflows/deploy-element.yml

@@ -0,0 +1,124 @@
+name: Deploy Element Web
+
+on:
+  schedule:
+    - cron: "0 0 * * *"
+  workflow_dispatch:
+
+concurrency:
+  group: "element-${{ github.ref }}"
+  cancel-in-progress: true
+
+jobs:
+  build-and-deploy:
+    name: 🏗️ Build and Deploy
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: 📦 Setup Node.js
+        uses: https://github.com/actions/setup-node@v4
+        with:
+          node-version: "22"
+
+      - name: 🔨 Clone, setup, and build Element Web
+        run: |
+          echo "Cloning Element Web..."
+          git clone https://github.com/maunium/element-web
+          cd element-web
+          git checkout develop
+          git pull
+
+          echo "Cloning matrix-js-sdk..."
+          git clone https://github.com/matrix-org/matrix-js-sdk.git
+
+          echo "Installing Yarn..."
+          npm install -g yarn
+
+          echo "Installing dependencies..."
+          yarn install
+
+          echo "Preparing build environment..."
+          mkdir -p .home
+
+          echo "Cleaning up specific node_modules paths..."
+          rm -rf node_modules/@types/eslint-scope/ matrix-*-sdk/node_modules/@types/eslint-scope || echo "Cleanup paths not found, continuing."
+
+          echo "Getting matrix-js-sdk commit hash..."
+          cd matrix-js-sdk
+          jsver=$(git rev-parse HEAD)
+          jsver=${jsver:0:12}
+          cd ..
+          echo "matrix-js-sdk version hash: $jsver"
+
+          echo "Getting element-web commit hash..."
+          ver=$(git rev-parse HEAD)
+          ver=${ver:0:12}
+          echo "element-web version hash: $ver"
+
+          chmod +x ./build-sh
+
+          export VERSION="$ver-js-$jsver"
+          echo "Building Element Web version: $VERSION"
+          ./build-sh
+
+          echo "Checking for build output..."
+          ls -la webapp/
+
+      - name: ⚙️ Create config.json
+        run: |
+          cat <<EOF > ./element-web/webapp/config.json
+          {
+            "default_server_name": "continuwuity.org",
+            "default_server_config": {
+              "m.homeserver": {
+                "base_url": "https://matrix.continuwuity.org"
+              }
+            },
+            "default_country_code": "GB",
+            "default_theme": "dark",
+            "mobile_guide_toast": false,
+            "show_labs_settings": true,
+            "room_directory": [
+              "continuwuity.org",
+              "matrixrooms.info"
+            ],
+            "settings_defaults": {
+              "UIFeature.urlPreviews": true,
+              "UIFeature.feedback": false,
+              "UIFeature.voip": false,
+              "UIFeature.shareQrCode": false,
+              "UIFeature.shareSocial": false,
+              "UIFeature.locationSharing": false,
+              "enableSyntaxHighlightLanguageDetection": true
+            },
+            "features": {
+              "feature_pinning": true,
+              "feature_custom_themes": true
+            }
+          }
+          EOF
+          echo "Created ./element-web/webapp/config.json"
+          cat ./element-web/webapp/config.json
+
+      - name: 📤 Upload Artifact
+        uses: https://code.forgejo.org/actions/upload-artifact@v3
+        with:
+          name: element-web
+          path: ./element-web/webapp/
+          retention-days: 14
+
+      - name: 🛠️ Install Wrangler
+        run: npm install --save-dev wrangler@latest
+
+      - name: 🚀 Deploy to Cloudflare Pages
+        if: vars.CLOUDFLARE_PROJECT_NAME != ''
+        id: deploy
+        uses: https://github.com/cloudflare/wrangler-action@v3
+        with:
+          accountId: ${{ secrets.CLOUDFLARE_ACCOUNT_ID }}
+          apiToken: ${{ secrets.CLOUDFLARE_API_TOKEN }}
+          command: >-
+            pages deploy ./element-web/webapp
+            --branch="${{ github.ref == 'refs/heads/main' && 'main' || github.head_ref || github.ref_name }}"
+            --commit-dirty=true
+            --project-name="${{ vars.CLOUDFLARE_PROJECT_NAME }}-element"