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>

angular.json

@@ -31,6 +31,8 @@
               "@angular/localize/init"
             ],
             "assets": [
+              "src/favicon.ico",
+              "src/apple-touch-icon.png",
               "src/assets/images/cbsnexora-favicon.svg",
               "src/robots.txt",
               "src/manifest.json",
@@ -39,6 +41,11 @@
                 "glob": "**/*",
                 "input": "node_modules/tinymce",
                 "output": "assets/tinymce"
+              },
+              {
+                "glob": "lottie.min.js",
+                "input": "node_modules/lottie-web/build/player",
+                "output": "assets/js"
               }
             ],
             "styles": [