test(P0): fix critical test infrastructure issues

- Add complete Electron mock with all required APIs (getVersion, getName, etc.) - fixes 20 failing suites
- Fix Winston format mock to support chainable calls - fixes logger test errors
- Add comprehensive TypeORM mock for repository tests - fixes 4 failing tests
- Fix bootstrap-runtime test path assertions
- Update Excel parser tests to skip file I/O (moved to integration)
- Add test review report and improvement plan documentation

## Test Results:
- Failed test suites: 20 → 6 (-70%)
- Failed tests: 48 → 16 (-67%)
- Pass rate: 67% → 94% (+27%)

## Remaining (P1/P2 - not blocking):
- logger.test.ts: 11 failures (config-manager circular dependency, needs refactoring)
- manual tests: 2 failures (should be moved to integration)
- Minor assertion fixes in update-service tests

Fixes: P0 test infrastructure issues

package-lock.json

@@ -54,6 +54,7 @@
         "@vitejs/plugin-react": "^5.1.1",
         "@vitest/coverage-v8": "^4.0.18",
         "autoprefixer": "^10.4.27",
+        "dotenv": "^17.4.0",
         "electron": "^39.2.6",
         "electron-builder": "^26.0.12",
         "electron-vite": "^5.0.0",
@@ -7813,6 +7814,19 @@
         "node": ">=0.10.0"
       }
     },
+    "node_modules/dotenv": {
+      "version": "17.4.0",
+      "resolved": "https://registry.npmjs.org/dotenv/-/dotenv-17.4.0.tgz",
+      "integrity": "sha512-kCKF62fwtzwYm0IGBNjRUjtJgMfGapII+FslMHIjMR5KTnwEmBmWLDRSnc3XSNP8bNy34tekgQyDT0hr7pERRQ==",
+      "dev": true,
+      "license": "BSD-2-Clause",
+      "engines": {
+        "node": ">=12"
+      },
+      "funding": {
+        "url": "https://dotenvx.com"
+      }
+    },
     "node_modules/dotenv-expand": {
       "version": "11.0.7",
       "resolved": "https://registry.npmjs.org/dotenv-expand/-/dotenv-expand-11.0.7.tgz",