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  (unused, superseded by paginateVersions) and unused exception classes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/utils/provisioning_code.ts

@@ -1,5 +1,5 @@
 import { createHash } from 'node:crypto'
-import type { Configuration } from '../domain/configuration/configuration.js'
+import type { Configuration } from '#domain/configuration/configuration'
 
 /**
  * Computes a 12-character hex content hash of a Configuration's desired state.