The client only streams the strategies of the folder it is looking at, so a
cloud folder card at the root had nothing to draw. The folder tree query now
returns, per folder and across its subtree, the strategy count, the two
most-used maps, and the agents in play. Counts and maps come from the
strategies table. Agents live inside elements, so ops.applyBatch keeps a
derived strategyAgentSummaries row current after any content op; the
strategy row itself stays untouched, as the record-scoped write contract
requires. A one-off internal backfill fills the summary for strategies
written before this landed.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>