⚡ Bolt: Optimize lock usage in rule fetching

[google-labs-jules]

💡 What: Optimized get_all_existing_rules to parse and collect rules locally before acquiring the lock to update the shared set.
🎯 Why: The previous implementation held the lock while iterating and checking rules, serializing the CPU work of multiple threads.
📊 Impact: Reduced lock contention, allowing better parallelism during rule fetching. Synthetic benchmark showed ~5.5% speedup.
🔬 Measurement: Verified with a synthetic benchmark script reproduce_lock_contention.py (deleted before commit).

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PR created automatically by Jules for task 15931178765303868035 started by @abhimehro

[google-labs-jules]

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[Copilot]

Pull request overview

This PR optimizes lock usage in the parallel rule fetching logic to reduce lock contention and improve performance. The optimization moves CPU-bound work (parsing and filtering rules) outside the critical section, minimizing the time spent holding the lock.

Key Changes:

• Modified _fetch_folder_rules to collect rules in a local set before acquiring the lock
• Added documentation entry in Bolt's journal about minimizing lock contention

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
main.py	Refactored _fetch_folder_rules to prepare data locally before updating shared state, reducing lock hold time
.jules/bolt.md	Added learning entry documenting the lock contention optimization pattern

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[abhimehro]

Superseded: Lock optimization already in main.