feat: Implement smart time-based rate limiting v0.1.8

🎯 Major Rate Limiting Improvement - Research-Friendly Design

New Rate Limiting System:
✅ 12 calls per 5-minute window (vs 8 per session)
✅ 8 calls per 30-second burst protection
✅ Automatic time-based reset (no LM Studio restarts needed)
✅ Clear feedback with remaining calls and reset times

Key Benefits:
- Supports extended research sessions without interruption
- Prevents LLM spam while allowing legitimate research workflows
- Users can work continuously without restarting LM Studio
- Intelligent burst protection prevents overwhelming websites

Technical Implementation:
- Sliding window algorithm with timestamp tracking
- Dual-layer protection: burst + window limits
- Automatic cleanup of expired call history
- User-friendly error messages with precise wait times

This addresses the core user feedback that session-based limits were too restrictive for normal research use cases while maintaining responsible web scraping practices.

Breaking Change: Rate limiting behavior changed from session-based to time-based
Migration: No action needed - new system is more permissive

package.json

@@ -1,6 +1,6 @@
 {
     "name": "webfetch-mcp",
-    "version": "0.1.7",
+    "version": "0.1.8",
     "type": "module",
     "private": false,
     "description": "Production-ready MCP server for web search and content extraction. Live web access for your local AI with tunable search and clean content extraction.",