ci: add lint workflow, shellcheck fixes, and CI failure hookshot alert

- .gitea/workflows/lint.yml: new workflow running shellcheck on .sh files
  and eslint on hookshot/ JS transform scripts
- hookshot/.eslintrc.json: declare data/result as hookshot globals
- hookshot/ci-alert.js: new Matrix hookshot transform for CI failure alerts
- hookshot/deploy.sh: fix SC2155 (split local/assign), SC2034 (remove unused var)
- systemd/livekit-clear-port.sh: fix SC2148 (invalid shebang escape)
- cinny/dev-update.sh: fix SC2115 (use ${WEB_ROOT:?} to guard rm -rf)
- deploy/lxc151-hookshot.sh: add shellcheck source=/dev/null for sourced file
- .gitignore: ignore node_modules/
- package.json + package-lock.json: eslint@8 dev dependency

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitea/workflows/lint.yml

@@ -0,0 +1,32 @@
+name: Lint
+
+on:
+  push:
+    branches: ["**"]
+  pull_request:
+    branches: ["**"]
+
+jobs:
+  shell-lint:
+    name: Shell (shellcheck)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Install shellcheck
+        run: apt-get update -qq && apt-get install -y -qq shellcheck
+
+      - name: Run shellcheck
+        run: find . -name "*.sh" -exec shellcheck {} +
+
+  js-lint:
+    name: JS (eslint)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Install ESLint
+        run: npm install --save-dev eslint@8
+
+      - name: Run ESLint
+        run: npx eslint --ext .js hookshot/