fix: resolve review #004 findings W1-W4 + close review gate

W1 (call/protocol/abort-cascade-wiring): wire AbortCascade into
CallAdapter handle_stream for EVENT_ABORTED. Cascades with
AbortPolicy::AbortDependents, aborts root, no descendant frames on
wire (ADR-016 Decision 2). Two integration tests added.

W2 (core/endpoint-client-fingerprint): extract TLS client cert
fingerprint in dispatch_quinn (SHA256:<hex> of leaf cert DER via
peer_identity) and dispatch_iroh (ed25519:<hex> of peer NodeId).
Fingerprint format documented in auth.md. Server config change
(with_no_client_auth → request-but-don't-require) deferred to new
follow-up task core/endpoint-request-client-cert.

W3 (vault/mnemonic-debug-redaction): replace Mnemonic derive(Debug)
with manual redacting impl (phrase: "[REDACTED]"). Seed confirmed
no Debug impl. Redaction test added.

W4 (core/auth-apikey-resources): Option B — drop entry.resources from
spec. External identities (token/fingerprint) grant scopes only;
resource-scoped ACLs are composition-internal (ADR-015/022). auth.md
corrected + limitation documented. Two tests confirm empty resources.

review-post-impl-fixes: all 4 verified, workspace green (326 tests,
0 failures, 0 clippy warnings). Review #004 status → resolved.

Graph: 34 tasks, 12 gens.

tasks/vault/mnemonic-debug-redaction.md

@@ -1,7 +1,7 @@
 ---
 id: vault/mnemonic-debug-redaction
 name: Replace Mnemonic derive(Debug) with redacting impl to prevent seed phrase leak
-status: pending
+status: completed
 depends_on: []
 scope: single
 risk: low
@@ -107,4 +107,12 @@ fn test_mnemonic_debug_redacts_phrase() {
 
 > Small fix, but eliminates a latent root-of-trust leak. The same
 > pattern (custom redacting `Debug`) is already established in three
-> other places in this codebase — this task brings `Mnemonic` in line.
+> other places in this codebase — this task brings `Mnemonic` in line.
+
+## Summary
+
+Replaced `#[derive(Debug)]` on `Mnemonic` with a manual redacting impl
+(`phrase: "[REDACTED]"`). Added `test_mnemonic_debug_redacts_phrase`
+asserting no phrase word appears in `format!("{:?}", mnemonic)`.
+Confirmed `Seed` has no `Debug` impl (derives only `Clone, Zeroize`).
+`cargo test -p alknet-vault` and clippy clean.