fix: propagate scope lifetime evidence across client observations

Address MR review sequence 3: share accepted Scope Object binding evidence across Interface names, supersede older fetches on binding change/loss, and track separately observed Object refs even when Descriptor scope_ref is omitted. Private evidence stays bounded to Interface records and never replaces optional wire/call metadata; corroborated same-lifetime immutability remains enforced.

Add six regressions covering sibling name updates/ref loss, first-fetch stale responses, omitted scope_ref with Object-ref replacement/loss, out-of-order evidence, eviction, immutable in-flight results and same-lifetime metadata changes. Validation: 47 runtime + 13 adapter tests; narrow Protocol/HTTP; workspace check/tests/all-target tests; Nix Clippy -D warnings; warning-free docs; fmt/diff checks.

crates/wip-client/README.md

@@ -19,6 +19,8 @@ Interface acquisition and call APIs use `wip_protocol::InterfaceReference { scop
 
 A descriptor without an Interface Descriptor validator is immutable only within the lifetime of its scope Object, not forever at that path. Descriptors with validators are also bound to that scope lifetime. When accepted observations establish that a known scope binding has changed or been lost, dependent cached interface state is invalidated and cannot authorize a new call until explicitly reacquired. A superseded interface response must not restore an observation from the old lifetime. A previously prepared call retains its original context rather than silently adopting a new scope identity or descriptor.
 
+Scope binding evidence is shared across Interface names at the same scope path: a new binding learned by fetching one name retires older descriptors for the other names too. Separately observed Object refs also provide lifetime evidence even when a descriptor's `scope_ref` was omitted. This corroboration is private bounded cache state, not an invented identity, and never fills in missing call metadata. Same-lifetime descriptor validation still applies; a detected ref change or loss retires the old lifetime instead.
+
 Object deletion, entry-edge removal, and local cache eviction are different events. A direct observe `NotFound` confirms unavailability at the requested scope path and removes cached interfaces scoped to that path; it does not guarantee identity-wide Object deletion or unavailability through every alias. Removing one entry edge likewise does not prove that the Object was deleted or invalidate every remaining alias. Cache eviction is local loss of retained knowledge, not evidence of Host deletion. Losing a known binding at an interface's scope path nevertheless ends safe reuse of descriptors dependent on that binding, even if the same Object remains reachable elsewhere. Optional `scope_ref` can provide identity evidence, but clients do not fabricate it when it is absent.
 
 Without Object `ref` or `scope_ref` identity evidence, a replacement at the same scope path can be indistinguishable from the previous Object. The runtime cannot detect every ref-less replacement from path and descriptor contents alone; absence of detectable change is not proof that the scope lifetime continued.