⚡ Bolt: [performance improvement] Replace O(N^2) nested loop with O(N) hash map lookup for deduplication

[mapleleaflatte03]

💡 What: Replaced list-based deduplication (seen = [], seen.append(), not in seen) with set-based deduplication (seen = set(), seen.add()) in blocking_commitment_ids and blocked_peer_host_ids in both kernel/kernel/cases.py and intelligence/company/meridian_platform/cases.py.

🎯 Why: Using a list to track seen items and checking not in seen inside a loop results in O(N^2) time complexity due to linear lookups. Using a set provides O(1) lookups, bringing the overall time complexity of the deduplication loop to O(N).

📊 Impact: Significantly improves performance, especially when blocking_cases(org_id) yields a large number of cases, reducing CPU cycles spent on linear array scans.

🔬 Measurement: Observe CPU profiles when calling blocked_peer_host_ids or blocking_commitment_ids on large datasets; the time spent in these functions should scale linearly rather than quadratically.

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PR created automatically by Jules for task 8101297293496397468 started by @mapleleaflatte03

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