G2 — Tool authorization + memory security v2
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tests/trust/test_tools.py: 6 passed
tests/memory/test_security.py: 5 passed

Proven: every runnable registry tool has a declared risk profile; default deny
covers unknown tools (AF-TOOL-PROFILE-MISSING), unknown subjects
(AF-TOOL-AUTHZ-DENIED), explicit denies (AF-TOOL-DENIED) and risk classes
outside the grant (AF-TOOL-RISK-DENIED). Memory gates keep historical hard
rejections, quarantine trust-insufficient candidates (invisible to retrieval),
reject already-expired payloads, and review_quarantine releases only when the
full pipeline passes under the reviewed policy.
