feat(memory): add opt-in scoped memory tools

docs/SECURITY-REVIEW.md

@@ -42,3 +42,23 @@ files, symlinked install directories, and a tampered manifest.
   branches.
 - `npm pack --dry-run` — passed; included runtime files, selected content,
   licenses, notice, and README.
+
+## Optional memory review (2026-10-08)
+
+Memory tools are not registered unless `memory.enabled` is explicitly true.
+Session keys include hashes of the OpenCode project identity and session ID;
+project-scope access additionally requires `memory.project: true` and is keyed
+to the canonical project. Each operation checks the session's project ID. Data
+is only stored or returned through explicit tool calls; list previews and
+retrieval become ordinary tool output visible to the active provider. The
+package does not encrypt storage, capture session content, or background-upload
+memory. Retention is lazy: expired entries are rejected and removed on access,
+not by a scheduled purge. Provider-backed learning and persistence across live
+OpenCode restarts have not been verified, so this is not a security audit or a
+claim about the underlying storage implementation.
+
+Deterministic checks cover disabled-by-default behavior, session separation,
+project opt-in, project separation, cross-project rejection, explicit deletion,
+and expiry. A plugin config object containing user options is preserved during
+uninstall; users must remove that entry themselves if they converted the
+installer-added string to configure memory.