v0.6.0

New profile and run commands, async function instrumentation, and hardware timestamp counters for lower overhead.

Added

• piano profile command: one-step build, execute, and report workflow with --ignore-exit-code and -- argument passthrough
• piano run command: execute the last-built instrumented binary with -- argument passthrough
• Async function instrumentation: async functions are now profiled instead of skipped; Guard detects thread migration and records wall time safely across .await points
• Calibration harness for measuring instrumentation bias and overhead

Fixed

• Allocation counter widened from u32 to u64, preventing silent truncation on high-allocation programs (#55)
• Worker-thread percentiles show "-" instead of misleading aggregated values (#56)
• Synthetic frames created for companion-merged worker threads, preventing silent data loss (#57)
• flush() writes to project-local target/piano/runs/ instead of global directory (#84)
• diff_runs uses i128 for alloc_count delta, preventing wrap on extreme values (#101)
• const, unsafe, and extern functions skipped during instrumentation instead of causing compile errors (#102)
• Fork/adopt injection skipped for detached thread spawns (std::thread::spawn, rayon::spawn), preventing lifetime errors (#103)

Changed

• Timing uses hardware TSC counters (Apple Silicon CNTVCT, x86 RDTSC) instead of Instant::now(), reducing per-call overhead
• Timestamp capture reordered to minimize bias in self-time measurement