Add self-hosted kids calendar app

Express + SQLite (node:sqlite, no native build step) family calendar:
parent accounts with household invites, per-child calendars with
save/duplicate/print, a token-gated read-only kiosk view for tablets,
and polling to keep parent and kiosk views in sync. Defaults to port 3007.

package.json

@@ -0,0 +1,19 @@
+{
+  "name": "kids-calendar",
+  "version": "1.0.0",
+  "description": "Self-hosted family weekly calendar with parent editing and a read-only kid kiosk view.",
+  "main": "server.js",
+  "private": true,
+  "engines": {
+    "node": ">=22.5.0"
+  },
+  "scripts": {
+    "start": "node server.js"
+  },
+  "dependencies": {
+    "bcryptjs": "^2.4.3",
+    "express": "^4.19.2",
+    "express-rate-limit": "^7.4.0",
+    "express-session": "^1.18.0"
+  }
+}