Initial commit: Developer Tools MVP with visual editor

- Complete React app with 7 developer tools
- JSON Tool with visual structured editor
- Serialize Tool with visual structured editor
- URL, Base64, CSV/JSON, Beautifier, Diff tools
- Responsive navigation with dropdown menu
- Dark/light mode toggle
- Mobile-responsive design with sticky header
- All tools working with copy/paste functionality

node_modules/fast-uri/.github/workflows/package-manager-ci.yml

@@ -0,0 +1,20 @@
+name: package-manager-ci
+
+on:
+  push:
+    branches:
+     - main
+     - master
+     - next
+     - 'v*'
+    paths-ignore:
+      - 'docs/**'
+      - '*.md'
+  pull_request:
+    paths-ignore:
+      - 'docs/**'
+      - '*.md'
+
+jobs:
+  test:
+    uses: fastify/workflows/.github/workflows/plugins-ci-package-manager.yml@v5