chore(release): 2.0.1

Patch release covering three internal refactors (see PRs #7, #8, #9):

- Extract shared constants, parameterize validators, simplify factory
- Pull validateConnection / validateModelName / error mapping into base
- Split OpenWebUI into strategy classes by backend

Public API surface and method signatures are unchanged. A handful of
error message strings were reworded (error type and status code remain
identical), and BaseAIProvider gained new protected hooks with no-op
defaults.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "simple-ai-provider",
-  "version": "2.0.0",
+  "version": "2.0.1",
   "description": "A simple and extensible AI provider package for easy integration of multiple AI services",
   "main": "dist/index.js",
   "module": "dist/index.mjs",