feat: add ntfy push notifications for daily digest and per-prayer reminders

- Server-side cron (node-cron) checks every minute for scheduled notifications
- Daily digest: sends all active prayers as a summary at a configured time
- Per-prayer reminders: pick days of the week per prayer; fires at configured time
- Settings panel in UI to configure ntfy topic, digest time, reminder time
- Test notification button to verify ntfy is working
- Settings stored in data/settings.json (persisted alongside prayers)

package-lock.json

@@ -10,7 +10,8 @@
       "dependencies": {
         "cors": "^2.8.6",
         "docx": "^9.7.1",
-        "express": "^5.2.1"
+        "express": "^5.2.1",
+        "node-cron": "^4.6.0"
       },
       "devDependencies": {
         "@testing-library/dom": "^10.4.1",
@@ -12613,6 +12614,15 @@
         "tslib": "^2.0.3"
       }
     },
+    "node_modules/node-cron": {
+      "version": "4.6.0",
+      "resolved": "https://registry.npmjs.org/node-cron/-/node-cron-4.6.0.tgz",
+      "integrity": "sha512-Si/bzYiKRHOB8/a99T2+SDGN582ONDMSTlJr5oCkT6GtnqPjZ2s10eoQRYkW9ZHwjVxONL+W8Fb+qR0AHMQsdg==",
+      "license": "ISC",
+      "engines": {
+        "node": ">=20"
+      }
+    },
     "node_modules/node-exports-info": {
       "version": "1.6.2",
       "resolved": "https://registry.npmjs.org/node-exports-info/-/node-exports-info-1.6.2.tgz",
@@ -17097,6 +17107,24 @@
         }
       }
     },
+    "node_modules/tailwindcss/node_modules/yaml": {
+      "version": "2.9.0",
+      "resolved": "https://registry.npmjs.org/yaml/-/yaml-2.9.0.tgz",
+      "integrity": "sha512-2AvhNX3mb8zd6Zy7INTtSpl1F15HW6Wnqj0srWlkKLcpYl/gMIMJiyuGq2KeI2YFxUPjdlB+3Lc10seMLtL4cA==",
+      "dev": true,
+      "license": "ISC",
+      "optional": true,
+      "peer": true,
+      "bin": {
+        "yaml": "bin.mjs"
+      },
+      "engines": {
+        "node": ">= 14.6"
+      },
+      "funding": {
+        "url": "https://github.com/sponsors/eemeli"
+      }
+    },
     "node_modules/tapable": {
       "version": "2.3.3",
       "resolved": "https://registry.npmjs.org/tapable/-/tapable-2.3.3.tgz",