ci: drop upstream GitHub CI workflows (backend-ci/frontend-ci/shellcheck)

These target GitHub Actions runners and do not fit the bare Gitea Actions
host runner, producing failed runs on every branch push. The build.yml
release workflow (auto-build on tags) is kept.

.github/workflows/backend-ci.yml

@@ -1,88 +0,0 @@
-name: Backend CI
-
-permissions:
-  contents: read
-
-on:
-  pull_request:
-    paths:
-      - 'tachyon/files/**'
-      - 'tachyon/Makefile'
-      - 'build.sh'
-      - 'tests/**'
-      - 'luci-app-tachyon/**'
-      - 'fe-app-tachyon/locales/**'
-      - '.github/workflows/build.yml'
-      - '.github/workflows/backend-ci.yml'
-  push:
-    branches:
-      - main
-    paths:
-      - 'tachyon/files/**'
-      - 'tachyon/Makefile'
-      - 'build.sh'
-      - 'tests/**'
-      - 'luci-app-tachyon/**'
-      - 'fe-app-tachyon/locales/**'
-      - '.github/workflows/build.yml'
-      - '.github/workflows/backend-ci.yml'
-
-jobs:
-  backend-checks:
-    name: Backend Runtime Checks
-    runs-on: ubuntu-24.04
-
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        with:
-          fetch-depth: 0
-
-      - name: Build ucode
-        shell: bash
-        run: |
-          sudo rm -f /etc/apt/sources.list.d/google-chrome.list
-          sudo apt-get update
-          sudo apt-get install -y build-essential cmake git libjson-c-dev pkg-config nodejs curl
-          git clone --depth 1 --branch v0.0.20250529 https://github.com/jow-/ucode.git /tmp/ucode
-          cmake -S /tmp/ucode -B /tmp/ucode/build \
-            -DUBUS_SUPPORT=OFF \
-            -DUCI_SUPPORT=OFF \
-            -DULOOP_SUPPORT=OFF
-          cmake --build /tmp/ucode/build --parallel
-          sudo cmake --install /tmp/ucode/build
-          sudo ldconfig
-          command -v ucode
-          ucode -e 'print("ucode ready\n")'
-
-      - name: Check ucode syntax
-        shell: bash
-        run: |
-          find tachyon/files/usr/lib -name '*.uc' -print0 | xargs -0 -n1 ucode -c -o /dev/null
-          find tachyon/files/usr/lib -name '*.uc' -print0 | xargs -0 -n1 ucode -S -c -o /dev/null
-
-      - name: Run backend tests
-        shell: bash
-        run: |
-          find tests -maxdepth 1 -name '*.sh' \
-            ! -name 'docker_e2e_test.sh' \
-            ! -name 'container_entrypoint.sh' \
-            ! -name 'run_all.sh' \
-            ! -name 'ucode_syntax_lint.sh' \
-            -print0 | xargs -0 -n1 -P4 bash
-
-  openwrt-e2e:
-    name: OpenWrt Docker E2E
-    needs: backend-checks
-    runs-on: ubuntu-24.04
-    timeout-minutes: 60
-
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-        with:
-          fetch-depth: 0
-
-      - name: Run OpenWrt E2E suite
-        shell: bash
-        run: bash tests/docker_e2e_test.sh

.github/workflows/frontend-ci.yml

@@ -1,93 +0,0 @@
-name: Frontend CI
-
-permissions:
-  contents: read
-
-on:
-  pull_request:
-    paths:
-      - 'fe-app-tachyon/**'
-      - 'luci-app-tachyon/po/**'
-      - '.github/workflows/frontend-ci.yml'
-  push:
-    branches:
-      - main
-    paths:
-      - 'fe-app-tachyon/**'
-      - 'luci-app-tachyon/po/**'
-      - '.github/workflows/frontend-ci.yml'
-
-jobs:
-  frontend-checks:
-    name: Frontend Quality Checks
-    runs-on: ubuntu-24.04
-    defaults:
-      run:
-        working-directory: fe-app-tachyon
-
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-
-      - name: Setup Node.js
-        uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
-        with:
-          node-version: '22'
-          cache: npm
-          cache-dependency-path: fe-app-tachyon/package-lock.json
-
-      - name: Install dependencies
-        run: npm ci
-
-      - name: Check formatting
-        id: format
-        run: |
-          npm run format
-          if ! git diff --exit-code; then
-            echo "::error::Code is not formatted. Run 'npm run format' locally."
-            exit 1
-          fi
-
-      - name: Run linter
-        run: npm run lint -- --max-warnings=0
-
-      - name: Run tests
-        run: npm test -- --run
-
-      - name: Check translation extraction
-        id: locale_extract
-        run: |
-          npm run locales:extract-calls
-          if ! git diff --exit-code -- locales/calls.json; then
-            echo "::error::Translation call index is stale. Run 'npm run locales:extract-calls' locally."
-            exit 1
-          fi
-
-      - name: Check distributed locales
-        id: locale_distribute
-        run: |
-          npm run locales:distribute
-          if ! git diff --exit-code -- ../luci-app-tachyon/po; then
-            echo "::error::LuCI locale copies are stale. Run 'npm run locales:distribute' locally."
-            exit 1
-          fi
-
-      - name: Build project
-        id: build
-        run: |
-          npm run build
-          if ! git diff --exit-code -- ../luci-app-tachyon/htdocs; then
-            echo "::error::Build generated changes. Check build output."
-            exit 1
-          fi
-
-      - name: Summary
-        if: always()
-        run: |
-          echo "## Frontend CI Results" >> $GITHUB_STEP_SUMMARY
-          echo "" >> $GITHUB_STEP_SUMMARY
-          echo "- Format check: ${{ steps.format.outcome }}" >> $GITHUB_STEP_SUMMARY
-          echo "- Translation extraction: ${{ steps.locale_extract.outcome }}" >> $GITHUB_STEP_SUMMARY
-          echo "- Locale distribution: ${{ steps.locale_distribute.outcome }}" >> $GITHUB_STEP_SUMMARY
-          echo "- Overall lint/tests status: ${{ job.status }}" >> $GITHUB_STEP_SUMMARY
-          echo "- Build: ${{ steps.build.outcome }}" >> $GITHUB_STEP_SUMMARY

.github/workflows/shellcheck.yml

@@ -1,62 +0,0 @@
-name: Differential ShellCheck
-
-on:
-  workflow_dispatch:
-  push:
-    branches:
-      - main
-      - 'rc/**'
-    paths:
-      - 'build.sh'
-      - 'install.sh'
-      - 'tachyon/files/etc/init.d/**'
-      - 'tachyon/files/usr/lib/cgi-bin/**'
-      - 'tachyon/files/etc/hotplug.d/iface/**'
-      - 'luci-app-tachyon/root/etc/uci-defaults/**'
-      - 'tests/**/*.sh'
-      - '.github/workflows/shellcheck.yml'
-  pull_request:
-    branches:
-      - main
-      - 'rc/**'
-    paths:
-      - 'build.sh'
-      - 'install.sh'
-      - 'tachyon/files/etc/init.d/**'
-      - 'tachyon/files/usr/lib/cgi-bin/**'
-      - 'tachyon/files/etc/hotplug.d/iface/**'
-      - 'luci-app-tachyon/root/etc/uci-defaults/**'
-      - 'tests/**/*.sh'
-      - '.github/workflows/shellcheck.yml'
-
-permissions:
-  contents: read
-
-jobs:
-  shellcheck:
-    name: Differential ShellCheck
-    runs-on: ubuntu-24.04
-    
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
-
-      - name: Install ShellCheck
-        run: |
-          sudo rm -f /etc/apt/sources.list.d/google-chrome.list
-          sudo apt-get update
-          sudo apt-get install -y shellcheck
-
-      - name: ShellCheck
-        shell: bash
-        run: |
-          mapfile -d '' scripts < <(
-            find . -type f \
-              \( -name '*.sh' -o -path './build.sh' -o -path './install.sh' \
-                 -o -path './tachyon/files/etc/init.d/*' \
-                 -o -path './tachyon/files/usr/lib/cgi-bin/*' \
-                 -o -path './tachyon/files/etc/hotplug.d/iface/*' \
-                 -o -path './luci-app-tachyon/root/etc/uci-defaults/*' \) \
-              -print0
-          )
-          shellcheck --severity=error "${scripts[@]}"