Add a new heatmap output to the tachyon profiler
It would be helpful to have a --heatmap output format that shows line-by-line sample intensity, similar to coverage.py's HTML reports.
Flamegraphs show which functions are hot and how they're called, but they don't tell you which lines within a function are the bottlenecks. The heatmap would solve this by showing the actual source code with color-coded lines (blue to red) based on sample counts, making it easy to spot hot loops, expensive operations, or unexpected hotspots within a function.
Usage would be: python -m profiling.sampling --heatmap -o results script.py