feat(cache): show remote cache hits

[wan9chi]

Motivation

#756 restores task results from the remote cache, but a remote hit looks the same as a local one. Showing where a hit came from makes it clear that the remote cache is working and how much of a run it served.

A cache hit now records whether it came from the local or the remote cache. Remote hits are marked, and local hits look as before:

• Inline: $ vtt write-file dist/output.txt built ◉ remote cache hit, replaying
• Compact summary, single task: vp run: remote cache hit, 1.2s saved.
• Compact summary, several tasks: vp run: 2/2 cache hit (100%, 1 remote).
• --last-details statistics: Statistics: 2 tasks • 2 cache hits (1 remote) • 0 cache misses
• --last-details task details: → Remote cache hit - output replayed - 1.2s saved

The saved summary records the source for --last-details. A summary saved without it reads as local hits.

The restore snapshot now shows the remote hit, and a new ignored local_and_remote_hits case runs a remote hit and a local hit together, followed by --last-details.

[github-actions]

fspy benchmark

linux

dynamic/launch             change  +1.26%  [ -5.11% ..  +8.61%]  overhead  +302.68%
dynamic/access             change  +0.31%  [-14.85% ..  +5.42%]  overhead   +11.37%
dynamic/access-relative    change  -0.42%  [-14.19% ..  +2.18%]  overhead   +59.68%
dynamic/access-contended   change  +0.50%  [-12.11% .. +15.67%]  overhead   +23.74%
static/launch              change  +0.11%  [ -5.07% ..  +6.84%]  overhead  +731.56%
static/access              change  -0.02%  [-14.53% .. +16.48%]  overhead  +818.60%
static/access-relative     change  -0.32%  [ -7.15% ..  +2.58%]  overhead +1372.53%
static/access-contended    change  +0.52%  [ -2.08% ..  +2.27%]  overhead +3200.67%

macos

dynamic/launch             change  -0.55%  [ -4.25% ..  +4.17%]  overhead  +210.87%
dynamic/access             change  -0.34%  [ -3.70% ..  +3.31%]  overhead    +4.01%
dynamic/access-relative    change  -0.10%  [ -2.77% ..  +2.77%]  overhead  +286.09%
dynamic/access-contended   change  -0.01%  [-12.35% .. +12.02%]  overhead    +2.29%

windows

dynamic/launch             change  +0.14%  [ -6.86% ..  +6.46%]  overhead   +26.79%
dynamic/access             change  +0.00%  [ -0.92% ..  +0.75%]  overhead    +1.13%
dynamic/access-relative    change  -0.18%  [ -1.24% ..  +0.71%]  overhead    +1.62%
dynamic/access-contended   change  +0.00%  [ -1.93% ..  +3.13%]  overhead    +1.58%