Add an experimental opt in tar based implementation of the local cache

[christiango]

We're seeing that for operations that are fast (such as transpiling with SWC) lage caching overhead is extremely high from copying the files over to the cache. This implements a local cache that uses tar for storing the cache. Here is the performance delta for this implementation from an internal repo

Platform	Cold cache on branch (avg)	Cold cache master (avg)	Speedup
Windows (NTFS)	19.31s	34.78s	1.8x
M1 Mac (APFS)	17.53s	42.07s	2.4x
Codespaces (Linux)	14.0s	20.4s	1.5x
WSL (ext4)	13.49s	15.60s	1.2x

And for reference here is the overhead before and after compared to lage --no-cache on that same repo

Platform	No cache (avg)	Cold cache on branch (avg)	Cold cache on master (avg)	Tar vs no-cache	Master vs no-cache
Windows (NTFS)	14.25s	19.31s	34.78s	1.4x slower	2.4x slower
M1 Mac (APFS)	14.41s	17.53s	42.07s	1.2x slower	2.9x slower
Codespaces (Linux)	13.2s	14.0s	20.4s	1.1x slower	1.5x slower
WSL (ext4)	12.34s	13.49s	15.60s	1.1x slower	1.3x slower

Key takeaway: Master's file-copy cache adds 1.3x–2.9x overhead vs no cache at all. The tar cache reduces that overhead to just 1.1x–1.4x, making cold-cache builds nearly as fast as uncached builds.