Wrap read-from-string/read with (let ((*read-eval* nil)) ...) at three
untrusted-input code paths:
1. think() in core-loop-reason — LLM output parsing. LLM output is
untrusted by definition; #.(shell ...) in a response must not execute.
2. action-system-execute in core-loop-act — :system :eval path processes
untrusted payload code from the signal pipeline.
3. load-memory-from-disk in core-memory — memory.snap file could be
corrupted or planted in ~/, must not execute #. reader macros.
Adds test-read-eval-rce-blocked to pipeline-reason-suite: mocks a
backend returning malicious output containing #.(setf ...), verifies
no side effects occur and safe fallback is returned.
RED proof recorded: *read-eval* T + #.(setf ...) → :PWNED (RCE active)
GREEN proof: *read-eval* NIL → reader-error caught (RCE blocked)
Test: reason 12/0, full suite 88/0
Amr Gharbeia
a31f19045a