chore: update dependencies and environment configuration

- Updated Claude settings to enable shadcn MCP server
- Removed env.example file (replaced with example.env)
- Updated package-lock.json with latest dependencies
- Added example.env file for environment variable configuration

🤖 Generated with [Claude Code](https://claude.ai/code)

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

.claude/settings.local.json

@@ -10,7 +10,8 @@
       "mcp__playwright__browser_take_screenshot",
       "mcp__playwright__browser_close",
       "Bash(git add:*)",
-      "Bash(git log:*)"
+      "Bash(git log:*)",
+      "Bash(git commit:*)"
     ],
     "additionalDirectories": [
       "C:\\c\\Projects\\nextjs-better-auth-postgresql-starter-kit"
@@ -18,6 +19,6 @@
   },
   "enableAllProjectMcpServers": true,
   "enabledMcpjsonServers": [
-    "context7"
+    "shadcn"
   ]
 }