⚡ Bolt: Optimize list_work performance

[google-labs-jules]

💡 What: Replaced external process spawns (basename, sed, grep) in list_work loop with shell builtins (${var##*/}, ${var:offset}, read).
🎯 Why: Process spawning inside a loop is expensive (N+1 problem). This caused list_work to be slow (~10ms per item).
📊 Impact: Reduced list_work time by ~98% (577ms -> 11ms for 50 items).
🔬 Measurement: Verified with benchmark_work_manager.sh script (created and deleted during process). Validated with tests/unit/test_work_manager.bats.

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PR created automatically by Jules for task 6457147374929505319 started by @oyi77

[google-labs-jules]

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