Implements IEnvironmentCheck for the four checks derivable without a
Claude CLI probe:
- GitCheck (Error) - resolves git via ExecutableResolver (handles .cmd
shims), parses `git --version`.
- GitIdentityCheck (Warning) - user.name/user.email presence; Unknown
(not Failed) if git itself is missing, so it doesn't duplicate GitCheck's
failure.
- PortCheck (Warning) - loopback bind probe for SignalRPort/ExternalMcpPort;
resolves the owning process via a new NetstatPortOwnerResolver and treats
a port held by the running ClaudeDo.Worker (update/repair case) as Ok.
Both ports are configurable, hence a warning.
- WriteAccessCheck (Error) - create+delete a probe file in InstallDirectory
and ~/.todo-app (walking up to the first existing parent), not an ACL
read (ACLs lie on virtualized paths).
Process calls go through a new IProcessRunner wrapping the existing static
ProcessRunner, so checks are fakeable in tests instead of spawning real
processes.
DotnetRuntimeCheck was intentionally not added: per
docs/explore-notes/installer-preflight.md, App/Worker publish
self-contained (no preinstalled runtime needed), and the Installer's own
.NET 8 Desktop Runtime requirement is self-proving - a framework-dependent
apphost can't reach managed code at all if that runtime is missing, so a
check running from inside the process can never observe a failure.
Brings in two prerequisite commits this task builds on that hadn't reached
this branch yet: the IEnvironmentCheck/EnvironmentCheckService scaffolding
and the installer-preflight.md research note.
