feat: a lone write is an invocation, whichever method spells it

[ShocOne]

Closes the first of the two gaps docs/mapping.md records (#103).

What was wrong

classify.go recognised an action only as a collection POST. An API that
spells an invocation as a replacement offers a lone PUT or PATCH instead —
and that entity classified as nothing. The write was filed as a collection
write no consumer reads, or as an update with no lifecycle around it, and the
entity was dropped as "no operations in classifiable positions" or
"partial lifecycle (update) fits no kind".

What changes

A write with nothing to read it back, list it or remove it is an invocation
whichever method carries it. It goes in the create slot beside every other
action's, so a consumer finds it in one place regardless of the method the
document used — derive.action needed no change.

An entity offering a write in both positions and nothing else still
classifies as nothing: two candidate invocations and no way to choose between
them, which is worth refusing rather than guessing.

The singleton is disjoint by construction, not by ordering — it needs a
collection GET, and the new rule requires there be none.

Also corrects two Kind comments in the file: KindListResource described
the list-only meaning docs/glossary.md explicitly retired, and KindAction
named the POST it is no longer limited to.

Effect on the pinned documents

Classification counts, measured before and after on the two documents in
corpus.lock.json:

Document	actions before	after	excluded before	after
thousandeyes	52	53	7	6
github	80	97	100	83

Resource, datasource and list-resource counts are unchanged on both. The
change is purely additive: every entity it moves came from the excluded pile.

Two existing test cases asserted the old behaviour — crud("/knobs/{knobId}", "patch!") and crud("/odd", "put!") both expected exclusion — and now assert
the action. Added a table-driven test proving the invocation lands in the
create slot with its own method, for all four positions, and that it is not
also recorded as surplus.

Note on README.md

README.md:55 reports 210 actions across three documents. That figure is now
understated, but it is a post-binding count over Jamf Pro as well, and Jamf Pro
is not in corpus.lock.json — so it cannot be re-measured here without a full
generation run. Left alone rather than restated from classification counts,
which are a different measurement.

Verification

make check passes: fmt, build, vet, coverage gate at 91.3% total (specmodel
95.0%), hygiene.

🤖 Generated with Claude Code