refactor: migrate all internal imports to package.json subpath aliases

- Add #domain, #protocol, #utils aliases to package.json imports map
- Replace all relative imports (./, ../, ../..) in app/ and
  database/mongo_migrations/ with the corresponding #alias imports,
  eliminating relative path traversal across the codebase
- Remove dead code: ConfigurationVersionModel.findByConfigurationIdentifier
  (unused, superseded by paginateVersions) and unused exception classes
  (NotFoundException, UnprocessableEntityException, DatabaseException)
  from app/exceptions/index.ts, keeping only BadRequestException
- Fix pre-existing syntax error in configuration_version.ts (mismatched
  parenthesis) that broke tsc
- Fix eqeqeq violation in configuration_service.ts and isNaN ->
  Number.isNaN in configuration_engine.ts / cwmp-1-0.ts / exchange_controller.ts
- Fix no-shadow violation in cwmp-1-0.ts EventStruct constructor
- Prettier formatting pass on touched files

Validated: tsc --noEmit clean, eslint app/ clean, full test suite green.

app/controllers/exchange_controller.ts

@@ -247,7 +247,10 @@ export default class ExchangeController {
 
     // Track SSE stream setup time
     const setupDurationMs = performance.now() - startTime
-    ExchangeMetricsService.getInstance().recordApiResponseTime('GET /exchanges/stream', setupDurationMs)
+    ExchangeMetricsService.getInstance().recordApiResponseTime(
+      'GET /exchanges/stream',
+      setupDurationMs
+    )
 
     const listener = (exchange: any) => {
       if (closed) return
@@ -333,10 +336,7 @@ export default class ExchangeController {
    *
    * Requirement 6.9: Event id equals the exchange's sequenceNumber
    */
-  private sendSSEEvent(
-    res: import('node:http').ServerResponse,
-    exchange: any
-  ): void {
+  private sendSSEEvent(res: import('node:http').ServerResponse, exchange: any): void {
     const data = JSON.stringify(exchange)
     res.write(`id: ${exchange.sequenceNumber}\ndata: ${data}\n\n`)
   }
@@ -347,7 +347,7 @@ export default class ExchangeController {
    */
   private isValidIso8601(value: string): boolean {
     const date = new Date(value)
-    if (isNaN(date.getTime())) {
+    if (Number.isNaN(date.getTime())) {
       return false
     }