Migrate the API to native ESM and vitest; pin Node 26

Prep PR for the admin auth module (docs/plan-admin-auth.md step 1).
better-auth 1.7 ships ESM only, so the API moves off CommonJS:

- "type": "module", module nodenext, target ES2024, .js suffixes on all
  relative imports, require('mariadb'|'cors') replaced by imports, and
  export= packages (winston, app-root-path, bcrypt) consumed via default
  imports. The logger now uses appRoot.path explicitly.
- TypeScript 5.9, @types/node 26, tslint removed. Node 26 pinned via
  engines and .nvmrc (Plesk runs 26).
- Jest 28 + ts-jest replaced by vitest 5. Eight test files depend on
  hoisted module mocks with static imports and resetModules + require,
  which Jest's ESM mode does not support; vitest keeps them nearly
  verbatim. Coverage via @vitest/coverage-v8 (lcov), Sonar generic report
  via vitest-sonar-reporter, so sonar-project.properties is unchanged.
  vitest.config.ts sets FEEDBACK_IP_SALT so the suite passes without a
  local .env.
- dotenv 8 -> 16 and axios 0.24 -> 1.x: their old typings are not
  resolvable under nodenext.
- autoCommit: false dropped from the pool configs; it is not a mariadb
  connector option and was silently ignored.

tsc clean, 96/96 tests green, compiled app boots and serves /, /docs and
CORS under Node ESM.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

package.json

@@ -3,22 +3,27 @@
 	"version": "0.1.0",
 	"description": "",
 	"main": "index.js",
+	"type": "module",
+	"engines": {
+		"node": ">=26"
+	},
 	"scripts": {
 		"start": "tsc && node ./dist/app.js",
 		"build": "tsc",
 		"debug": "export DEBUG=* && npm run start",
-		"test": "jest --coverage --testResultsProcessor ./node_modules/jest-sonar-reporter/index.js"
+		"test": "vitest run --coverage",
+		"test:watch": "vitest"
 	},
 	"keywords": [],
 	"author": "",
 	"license": "ISC",
 	"dependencies": {
 		"app-root-path": "^3.0.0",
-		"axios": "^0.24.0",
+		"axios": "^1.20.0",
 		"bcrypt": "^5.0.1",
 		"cors": "^2.8.5",
 		"debug": "^4.3.1",
-		"dotenv": "^8.2.0",
+		"dotenv": "^16.6.1",
 		"express": "^4.18.2",
 		"guid-typescript": "^1.0.9",
 		"mariadb": "^3.0.2",
@@ -30,26 +35,19 @@
 	"devDependencies": {
 		"@types/app-root-path": "^1.2.4",
 		"@types/bcrypt": "^3.0.1",
+		"@types/cors": "^2.8.19",
 		"@types/debug": "^4.1.5",
 		"@types/express": "^4.17.15",
-		"@types/jest": "^28.1.3",
-		"@types/node": "^18.11.17",
+		"@types/node": "^26.4.1",
 		"@types/random-words": "^1.1.2",
 		"@types/swagger-jsdoc": "^6.0.1",
 		"@types/swagger-ui-express": "^4.1.3",
 		"@types/winston": "^2.4.4",
+		"@vitest/coverage-v8": "^5.0.0",
 		"is-number": "^7.0.0",
-		"jest": "^28.1.1",
-		"jest-sonar-reporter": "^2.0.0",
 		"source-map-support": "^0.5.19",
-		"ts-jest": "^28.0.5",
-		"tslint": "^6.1.3",
-		"typescript": "^4.9.4"
-	},
-	"jestSonar": {
-		"sonar56x": true,
-		"reportPath": "testResults",
-		"reportFile": "sonar-report.xml",
-		"indent": 4
+		"typescript": "^5.9.3",
+		"vitest": "^5.0.0",
+		"vitest-sonar-reporter": "^3.0.0"
 	}
 }