docs: charter complexity phase 8 and record the two gates disagreeing - #404

make check fails its complexity step on two functions the 4b-3 ladder
never cleared -- git.guessDirName 27 (pkg/op/provider/git/helpers.go:182)
and cli.runSelfInstall 22 (internal/cli/selfinstall.go:211). Both predate
the #373 Windows campaign and neither was touched by it. They join the
plan as phase 8; the total moves 61 -> 63 and the plan returns to
in-progress.

The more useful finding is that the repository's two complexity gates
disagree. make complexity (standalone fzipp/gocyclo, threshold 20) fails
on both. make lint-all reports 0 issues on all three GOOS values even
though .golangci.yaml enables gocyclo at min-complexity 15.
runSelfInstall is explained -- it carries a //nolint:gocognit,gocyclo
that golangci honors and standalone gocyclo ignores. guessDirName is
not: no suppression anywhere in the file, no path exclusion covering it,
and running golangci-lint with only gocyclo enabled against that package
still returns 0 issues.

The hypothesis is that min-complexity is not reaching the linter --
golangci's own default is 30, which would explain silence at 27 and 22
alike -- but that was not confirmed, so it is recorded as an open
question rather than a diagnosis. Resolving it belongs to the phase: a
threshold that silently does not apply is a gate passing on nothing, so
the phase ends by confirming zero findings under both tools rather than
one.

Issue #312 is closed; the phase needs a reopen or its own tracking issue
before its PR. Noted in the plan as undecided rather than settled here.

Assisted-by: Claude
Signed-off-by: David Noble <[email protected]>