fix(#829): gate claudex and close branch coverage gaps

docs/architecture/lease-broker-security.md

@@ -6,7 +6,7 @@
 - Session IDs and cycle tokens use the OS cryptographic RNG. `Math.random` and model output are not token sources.
 - Framing and persistence failures fail closed. Sensitive tokens are not logged.
 - Built-in `0700`/`0600` filesystem modes provide same-principal hardening only, not socket authenticity against the same UID. WI-1 provides no distinct-principal isolation. That stronger deployment requires an external protected proxy, ACL, or service boundary, and the boundary must preserve authenticated client identity for the broker's `SO_PEERCRED` and ancestry authorization rather than substituting a shared proxy identity.
-- WI-2 whole-class authorization denies every consequential, unknown, and custom tool while UNVERIFIED; it does not inspect shell strings or trust wrapper selection.
+- WI-2 whole-class authorization denies every consequential, unknown, and custom tool while UNVERIFIED; it does not inspect shell strings or trust wrapper selection. First-class Claude/Pi and both Claudex dispatch modes use broker register-before-exec; Claudex additionally installs the mandatory all-tools hook inside its preserved isolated config and fails closed on unsafe settings.
 - WI-2 promotion consumes a WI-1 cycle token before VERIFIED becomes visible. Observer revocation, runtime-generation replacement, broker restart, and monotonic TTL expiry remove authority.
 - Receipt observation, payload construction, compaction observers, and constrained recovery implementation remain later surfaces. A receipt can become a promotion prerequisite but is never the safety mechanism.