The wheel-side chat_history MCP tool advertises a `before_ts`
parameter for backward paging through long histories, and the docs
describe it as the canonical pagination knob — but the server
silently ignored it until now. Without this fix, an agent passing
before_ts to chat_history would always get the most-recent N rows
and pagination would be broken end-to-end.
Add `before_ts` query param parsed as RFC3339 at the trust boundary
and translated into a `created_at < $X` clause on the existing
builder. Mirrors the strict-inequality shape since_id uses for
forward paging (`created_at > cursorTime`) so paging across both
directions has consistent semantics.
Tests: 3 new branches (positive filter, composition with peer_id
into the canonical chat_history paging shape, RFC3339 rejection
across 4 malformed inputs including URL-encoded SQL injection).
Mutation-verified pre-commit; existing 9 activity tests still pass.
Reported by self-review on PR #2474.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
15e1ea36de