⚡ Bolt: Optimize execute_3_way_match performance

[kourdroid]

💡 What: Refactored execute_3_way_match in src/plugins/supply_chain.py to precompute the normalized descriptions and tokens for Purchase Orders and Receipts before looping over the invoice items.
🎯 Why: To prevent an O(N*M) performance bottleneck where the algorithm recalculates string lowercasing, regex filtering, and token splitting on every candidate for every invoice line.
📊 Impact: Reduces matching overhead by ~80% for large matching tasks. A benchmark on 100 invoice lines and 1000 PO/Receipt items showed execution time dropping from 1.57s down to 0.25s.
🔬 Measurement: You can test this by running execute_3_way_match with hundreds of PO lines and noting the improved execution speed.

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PR created automatically by Jules for task 7522692603390545006 started by @kourdroid

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