Add comprehensive filtering system with hour-based datetime and property filters

This major enhancement addresses user needs for more precise filtering and introduces
powerful new capabilities for property searches:

Key Features:
- Hour-based date filtering (past_hours, datetime_from/to with ISO 8601 support)
- Server-side property filters (beds, baths, sqft, price, lot_sqft, year_built)
- Sorting support (list_date, sold_date, list_price, sqft, beds, baths)
- Full timestamp preservation (YYYY-MM-DD HH:MM:SS instead of date-only)
- Comprehensive validation with helpful error messages

Technical Changes:
- Preserve full datetime precision in processors.py and parsers.py
- Implement client-side hour-based post-filtering for all listing types
- Add server-side GraphQL filters for property characteristics
- Generalize filtering to work across SOLD, PENDING, FOR_SALE, FOR_RENT
- Add 15 comprehensive tests covering all new features
- Maintain full backward compatibility with existing parameters

Fixes #113 (sorting support)

Version bump to 0.7.0 reflects significant new functionality while maintaining
backward compatibility.

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

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

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "homeharvest"
-version = "0.6.2"
+version = "0.7.0"
 description = "Real estate scraping library"
 authors = ["Zachary Hampton <zachary@bunsly.com>", "Cullen Watson <cullen@bunsly.com>"]
 homepage = "https://github.com/ZacharyHampton/HomeHarvest"