feat(gemini): normalize base URL to strip API version suffixes

Automatically remove trailing slashes and version paths (e.g., /v1beta) from GEMINI_BASE_URL
Update GeminiAnalyzer to use the normalized URL and add type hints
Add test coverage for Gemini client configuration

src/uipath_explainator/config.py

@@ -2,6 +2,7 @@ from __future__ import annotations
 
 from dataclasses import dataclass
 from pathlib import Path
+import re
 from typing import Self
 
 from dotenv import load_dotenv
@@ -30,3 +31,10 @@ class Settings:
     def require_api_key(self) -> None:
         if not self.api_key:
             raise ValueError("Missing GEMINI_API_KEY (or GOOGLE_API_KEY) in the environment.")
+
+    def normalized_base_url(self) -> str | None:
+        if not self.base_url:
+            return None
+
+        base_url = self.base_url.strip().rstrip("/")
+        return re.sub(r"/v\d+(?:alpha|beta)?$", "", base_url, flags=re.IGNORECASE)