feat(scheduled-ops): add scheduled operations for Team Pro users (#231)

Adds the ability to schedule recurring Docker operations (stack restarts,
fleet snapshots, system prunes) via cron expressions with full execution
history logging. Includes Run Now for on-demand execution.

backend/package-lock.json

@@ -20,6 +20,7 @@
         "composerize": "^1.7.5",
         "cookie-parser": "^1.4.7",
         "cors": "^2.8.6",
+        "cron-parser": "^5.5.0",
         "dockerode": "^4.0.9",
         "express": "^5.2.1",
         "express-rate-limit": "^8.3.1",
@@ -1930,6 +1931,18 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/cron-parser": {
+      "version": "5.5.0",
+      "resolved": "https://registry.npmjs.org/cron-parser/-/cron-parser-5.5.0.tgz",
+      "integrity": "sha512-oML4lKUXxizYswqmxuOCpgFS8BNUJpIu6k/2HVHyaL8Ynnf3wdf9tkns0yRdJLSIjkJ+b0DXHMZEHGpMwjnPww==",
+      "license": "MIT",
+      "dependencies": {
+        "luxon": "^3.7.1"
+      },
+      "engines": {
+        "node": ">=18"
+      }
+    },
     "node_modules/cross-spawn": {
       "version": "7.0.6",
       "resolved": "https://registry.npmjs.org/cross-spawn/-/cross-spawn-7.0.6.tgz",
@@ -3642,6 +3655,15 @@
         "node": ">=10"
       }
     },
+    "node_modules/luxon": {
+      "version": "3.7.2",
+      "resolved": "https://registry.npmjs.org/luxon/-/luxon-3.7.2.tgz",
+      "integrity": "sha512-vtEhXh/gNjI9Yg1u4jX/0YVPMvxzHuGgCm6tC5kZyb08yjGWGnqAjGJvcXbqQR2P3MyMEFnRbpcdFS6PBcLqew==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=12"
+      }
+    },
     "node_modules/magic-string": {
       "version": "0.30.21",
       "resolved": "https://registry.npmjs.org/magic-string/-/magic-string-0.30.21.tgz",