The MCP get_agent_activity tool sliced the raw timeline before passing
to the curator, so `limit: 5` could land mid-message and return a
trailing fragment of streamed assistant text. Now goes through the
existing projection pipeline so the limit counts whole projected
entries — assistant deltas merged, tool calls collapsed by callId,
reasoning chunks merged.
Same bug fixed in the wait_for_agent timeout's "Recent activity"
preview, which used the same raw slice.
Consolidates the merge logic: activity-curator no longer ships its own
collapseTimeline, it delegates to projectTimelineRows. One source of
truth for "what is a complete message".
Drops the meaningless `provider` parameter that was threaded through
the projection module — merge logic never branched on it. The wire
schema keeps `provider` per entry; session stamps it once at the emit
boundary. Adds `reasoning_merge` to the projection kind enum (additive
wire change).
Mohamed Boudra
da85814940