POST THANKS HACK - DATABASE ERROR FIX
====================================

FIXED ISSUE:
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Error: Invalid SQL - Unknown column '0Array' in 'where clause'
Cause: The fetch_thanks() function was receiving an array as $postids parameter
       and converting it to string incorrectly, resulting in "0Array" in SQL

FILES MODIFIED:
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1. includes/functions_post_thanks.php
   - Added proper array handling in fetch_thanks() function
   - Added validation to filter empty/non-numeric values
   - Added fallback to use single postid when array is empty

2. product-post_thanks_utf8.xml
   - Added initialization check for $ids global variable
   - Ensures $ids is never undefined or empty

CHANGES MADE:
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In functions_post_thanks.php:
- Enhanced array validation in fetch_thanks() function
- Added filtering for empty/invalid array values
- Added proper fallback mechanism

In product-post_thanks_utf8.xml:
- Added defensive code to initialize $ids variable
- Prevents undefined variable errors

TESTING:
--------
1. Clear forum cache
2. Visit a thread with posts that have thanks
3. Verify no database errors occur
4. Check that thanks display correctly
5. Test adding/removing thanks functionality

This fix resolves the immediate database error while maintaining all existing functionality.