feat(ui): animated boot splash and loading screen

Show a Lottie-animated splash while the app bundle boots and dismiss it
once WebAppComponent initialises, plus a reusable mifosx-loading-screen
component with loading and error animations. lottie.min.js is served
from the lottie-web package instead of being vendored into src/assets.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

package-lock.json

@@ -41,6 +41,7 @@
         "jspdf-autotable": "^5.0.2",
         "lightgallery": "^2.9.0",
         "lodash": "4.17.23",
+        "lottie-web": "^5.13.0",
         "moment": "^2.29.4",
         "ngx-image-cropper": "^9.1.6",
         "ngx-mat-select-search": "^8.0.2",
@@ -18380,6 +18381,12 @@
         "url": "https://github.com/chalk/wrap-ansi?sponsor=1"
       }
     },
+    "node_modules/lottie-web": {
+      "version": "5.13.0",
+      "resolved": "https://registry.npmjs.org/lottie-web/-/lottie-web-5.13.0.tgz",
+      "integrity": "sha512-+gfBXl6sxXMPe8tKQm7qzLnUy5DUPJPKIyRHwtpCpyUEYjHYRJC/5gjUvdkuO2c3JllrPtHXH5UJJK8LRYl5yQ==",
+      "license": "MIT"
+    },
     "node_modules/lru-cache": {
       "version": "5.1.1",
       "resolved": "https://registry.npmjs.org/lru-cache/-/lru-cache-5.1.1.tgz",