⚡ Bolt: [performance improvement] Optimize version comparison

[mttmcknn]

💡 What: Replaced strings.Split with strings.Cut in compareVersions in internal/update/update.go and internal/plugin/manager.go.
🎯 Why: strings.Split allocates a slice which causes GC pressure in tight loops. strings.Cut provides a zero-allocation way to split strings sequentially.
📊 Impact: ~2.8x faster version string comparison, reducing allocations to zero.
🔬 Measurement: Benchmarked against the previous implementation, zero bytes allocated vs 288 bytes per operation (6 allocations).

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PR created automatically by Jules for task 1094966689686086549 started by @himattm

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