docs: propose a public remote cache on Cloudflare

[fengmk2]

Motivation

Open-source contributors need to reuse task results without credentials. Maintainers need a low-cost service that accepts uploads from trusted GitHub Actions jobs.

Propose a self-hosted remote cache for vp run on Cloudflare Workers, D1, and R2, based on #713. Reads are public. Writes use GitHub OIDC and require a push job on the registered repository's main branch. vp cache push publishes selected results explicitly.

The RFC includes setup and storage diagrams, operational limits, and Free/Paid capacity estimates. Measurements from four published Vite frontends support the cache-size assumptions.

[github-actions]

fspy benchmark

linux

dynamic/launch             change  -1.42%  [-10.14% ..  +8.61%]  overhead  +273.55%
dynamic/access             change  +0.12%  [-14.88% .. +37.48%]  overhead   +11.52%
dynamic/access-relative    change  -0.97%  [-23.31% ..  +2.66%]  overhead   +50.27%
dynamic/access-contended   change  -2.74%  [-17.00% ..  +9.10%]  overhead    +9.98%
static/launch              change  +0.87%  [ -8.60% ..  +9.38%]  overhead  +658.19%
static/access              change  -1.06%  [ -8.16% ..  +7.66%]  overhead  +896.24%
static/access-relative     change  -1.36%  [ -5.31% ..  +4.04%]  overhead +1303.29%
static/access-contended    change  +1.97%  [-10.18% .. +12.14%]  overhead +1977.06%

macos

dynamic/launch             change  +0.69%  [ -3.73% ..  +5.18%]  overhead  +225.55%
dynamic/access             change  +1.80%  [-13.59% .. +30.46%]  overhead    +4.07%
dynamic/access-relative    change  +0.53%  [-12.64% .. +25.92%]  overhead  +251.38%
dynamic/access-contended   change  +4.44%  [ -8.40% .. +589.39%]  overhead    +3.55%

windows

dynamic/launch             change  -2.34%  [ -7.52% ..  +6.98%]  overhead   +24.06%
dynamic/access             change  -0.90%  [-23.59% ..  +4.82%]  overhead    +0.35%
dynamic/access-relative    change  -0.87%  [-16.42% ..  +2.40%]  overhead    +1.24%
dynamic/access-contended   change  +0.00%  [ -4.65% .. +13.08%]  overhead    +3.22%