kdesc --coverage <target>: one target's view (from dev 931ea5490a5d)

For the designer building a target: the klammers that cover it, those
that do so with an empty definition (a decision that the klammer has no
meaning there), and the undecided ones (no definition). One klammer per
line, alphabetical; "all" adds the explanations; an unknown word names
the missing target.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

tst/coverage/target_view.k

@@ -0,0 +1,17 @@
+# Fixture for kdesc_test.sh: one target's view (--coverage <target>).
+# Engine tier: it declares its own targets, so the suite runs with no
+# klammer set.
+@@@target ta | Target A @@@
+@@@target tb | Target B @@@
+
+# Covers ta with a body.
+@@full.k s : defined for ta @@
+@@full.ta :: A*s* @@
+
+# Covers ta with an EMPTY body: a decision that it has no meaning in ta.
+@@nothing.k s : defined for ta by an empty body @@
+@@nothing.ta :: @@
+
+# Defined for tb only: undecided in ta.
+@@elsewhere.k s : defined for tb @@
+@@elsewhere.tb :: B*s* @@