Added comprehensive tests for loader (95.58% coverage)

[anshukaushik4700]

Summary

Adds comprehensive test coverage for loader.js with 22 tests covering the full bootstrap lifecycle — i18n initialization, DOM updates, highlight.js loading, Materialize integration, RequireJS configuration, async retry logic, fatal error paths, and all error callbacks.

Changes

22 comprehensive tests:

• requirejs.config validation (3)
• Global flags (1)
• Full success path (1)
• i18next init error handling (2)
• changeLanguage error handling (1)
• DOMContentLoaded (document loading state) (1)
• languageChanged event (1)
• highlight.js loading (3)
• updateContent early-return guard (1)
• Materialize / M.AutoInit (2)
• waitForGlobals retry loop (1)
• PRELOADED_SCRIPTS define() (2)
• Fatal createjs missing path (1)
• activity/activity errback (1)
• Core bootstrap errback (1)

Coverage Achieved

loader.js:

• Statements: 95.58% ✅
• Branches: 94.11% ✅
• Functions: 90.9% ✅
• Lines: 96.92% ✅

Verification

✅ Tests: 22 passed, 22 total
✅ All tests passing
✅ No failures
✅ Professional test patterns

Coverage Verification ✅

Verified locally: loader.js | 95.58 | 94.11 | 90.9 | 96.92 |

✅ Statements: 95.58%
✅ Branches: 94.11%
✅ Functions: 90.9%
✅ Lines: 96.92%

Command: npm test loader.test.js -- --coverage

PR Category

• Bug Fix
• Performance
• Features
• Tests
• Documentation

[github-actions]

✅ All Jest tests passed! This PR is ready to merge.

[github-actions]

✅ All Jest tests passed! This PR is ready to merge.

[anshukaushik4700]

@walterbender @omsuneri ready for review.