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/damerau-levenshtein/scripts/update-changelog.sh

@@ -0,0 +1,21 @@
+#! /usr/bin/env bash
+
+set -euo pipefail
+
+# To make it work on OSX (provided gnu-sed in installed)
+if type gsed 2> /dev/null
+then
+  alias sed=gsed
+fi
+
+
+version=$(jq --raw-output ' .version ' "package.json")
+date=$(date +%Y-%m-%d)
+
+sed \
+  --regexp-extended \
+  --in-place="" \
+  "s$^## \[Unreleased\]$\## [Unreleased\]\n\n\n## [${version}] - ${date}$" \
+  CHANGELOG.md
+
+git add CHANGELOG.md