Editing an existing comment's text is irreversible (not version-tracked),
which breaks the agent's "only reversible operations" invariant. Remove the
updateComment tool that was added in the toolset-expansion change, leaving the
agent at 40 tools (comments: create/resolve only).
- Remove the updateComment tool from forUser().
- Remove updateComment from the DocmostClientLike interface.
- Reword SAFETY_FRAMEWORK: comments are create/resolve only; drop the
comment-text-edit exception (keep the public-sharing one); keep the
no-permanent-deletion guarantee and anti-prompt-injection rules.
- Tests: assert updateComment is NOT exposed (mirrors the deleteComment guard).
- docs(ai-agent-chat-plan): move updateComment to the "not exposed" list.