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/foreground-child/dist/esm/proxy-signals.js

@@ -0,0 +1,34 @@
+import { allSignals } from './all-signals.js';
+/**
+ * Starts forwarding signals to `child` through `parent`.
+ */
+export const proxySignals = (child) => {
+    const listeners = new Map();
+    for (const sig of allSignals) {
+        const listener = () => {
+            // some signals can only be received, not sent
+            try {
+                child.kill(sig);
+                /* c8 ignore start */
+            }
+            catch (_) { }
+            /* c8 ignore stop */
+        };
+        try {
+            // if it's a signal this system doesn't recognize, skip it
+            process.on(sig, listener);
+            listeners.set(sig, listener);
+            /* c8 ignore start */
+        }
+        catch (_) { }
+        /* c8 ignore stop */
+    }
+    const unproxy = () => {
+        for (const [sig, listener] of listeners) {
+            process.removeListener(sig, listener);
+        }
+    };
+    child.on('exit', unproxy);
+    return unproxy;
+};
+//# sourceMappingURL=proxy-signals.js.map