Coding agent processes read directly from the kernel

Kaji's agent process monitor moved from the old arguments-by-PID scan to a native proc_pidinfo-based snapshotter that captures executable paths, thread counts, memory bytes, and process state directly from the Darwin kernel, without spawning subprocesses on the main thread.

• Added CodingAgentNativeProcessSnapshotter using Darwin.proc_pidinfo for memory, thread count, and executable path
• Added CodingAgentProcessArgumentSnapshotter for per-PID args via proc_args
• Added CodingAgentProcessPatternKiller for pkill-based agent process termination with pattern matching
• Replaced the old CodingAgentProcessParser with structured process info and pattern-based killing
• Replaced sparkles icon with cpu icon across process monitor UI
• Added tests for argument snapshotter, pattern killer, and classifier behavior
• Bumped Kaji to 0.1.91