feat(cache): resolve remote cache configuration

[wan9chi]

Motivation

Remote cache integration needs an effective endpoint and mode on each planned execution. Resolving settings only at process startup would miss flags and environment overrides in nested vp run commands.

Add workspace remoteCache.url, task-level remoteCache: false, --remote-cache=off/read/read-write, and the VP_REMOTE_CACHE and VP_REMOTE_CACHE_URL environment variables. Top-level and nested invocations share resolution: flags override the current environment, nested overrides stay scoped to their branch, and the default is read with an endpoint or off without one. Local cache disabling also disables remote access.

Validate modes and endpoints during planning, and keep remote controls out of task environments and cache fingerprints. Plan snapshots cover precedence, inheritance, sibling isolation, exclusions, errors, and Windows environment-name casing. Existing plan and execution snapshots remain unchanged.

This PR adds configuration resolution only. Remote transfers are not implemented, and CLI help states that limitation.

[socket-security]

Review the following changes in direct dependencies. Learn more about Socket for GitHub.

Diff	Package	Supply Chain Security	Vulnerability	Quality	Maintenance	License
	cargo/​syn@​3.0.6
	cargo/​url@​2.5.8

View full report

[github-actions]

fspy benchmark

linux

dynamic/launch             change  +0.33%  [-15.24% .. +17.36%]  overhead  +289.74%
dynamic/access             change  +0.00%  [ -4.43% ..  +4.59%]  overhead   +17.22%
dynamic/access-relative    change  +0.33%  [ -2.42% ..  +4.25%]  overhead   +65.79%
dynamic/access-contended   change  +0.19%  [ -8.85% ..  +6.25%]  overhead   +55.02%
static/launch              change  +0.01%  [ -8.50% .. +14.70%]  overhead  +654.09%
static/access              change  -0.07%  [ -0.96% ..  +0.70%]  overhead +1427.09%
static/access-relative     change  +0.23%  [ -1.17% ..  +1.23%]  overhead +1940.84%
static/access-contended    change  +0.40%  [ -0.29% ..  +1.32%]  overhead +1819.76%

macos

dynamic/launch             change  -0.42%  [ -3.29% ..  +3.01%]  overhead  +217.83%
dynamic/access             change  +0.00%  [ -4.01% ..  +2.50%]  overhead    +5.31%
dynamic/access-relative    change  -0.11%  [ -2.39% ..  +1.79%]  overhead  +263.96%
dynamic/access-contended   change  -0.85%  [ -5.13% ..  +2.76%]  overhead    +3.78%

windows

dynamic/launch             change  -0.61%  [ -3.63% ..  +2.38%]  overhead   +24.79%
dynamic/access             change  +0.00%  [ -0.75% ..  +0.97%]  overhead    +1.16%
dynamic/access-relative    change  +0.00%  [ -0.91% ..  +0.76%]  overhead    +1.12%
dynamic/access-contended   change  -0.18%  [ -1.43% ..  +1.10%]  overhead    +0.92%