test: make the ecosystem fault suite fail when the feature is deleted

Several assertions passed against code with the behaviour removed. The
independent-outage test shared no state to begin with, the capability
fixture used to prove read-only filtering was already mutating, and
route-level faults were simulated with a separate fake instead of the
shared one. The harness now takes per-route faults and a ticking clock,
so durations are measurable and one dead endpoint can be shown not to
mute a whole service. New cases cover a resolved reference with no
entity, a rejected credential, a malformed Praxis body, foreign items
in a scoped response, named truncation, traces staying out of facts,
and enrichment making progress while its oldest batch is backed off.

Found in review of #82.

cmd/mavend/ecosystem_test.go

@@ -59,8 +59,11 @@ func newHexisTestHandler(t *testing.T, resolveBody string, caps string) (*reacti
 	}, executed
 }
 
-func actDec(text string) router.Decision {
-	return router.Decision{Intent: router.IntentAct, Slots: router.Slots{Text: text, Fn: "restart", HasFn: true}}
+// actDec builds an act decision about subject. The verb is always "restart":
+// the argument is the utterance the entity is resolved from, never the verb,
+// so actDec("restart") reads as a verb and is not one.
+func actDec(subject string) router.Decision {
+	return router.Decision{Intent: router.IntentAct, Slots: router.Slots{Text: subject, Fn: "restart", HasFn: true}}
 }
 
 func TestHexisMutatingRequiresConfirm(t *testing.T) {