Function count_workspace_thinking 

pub fn count_workspace_thinking(engine: &Engine) -> usize

Workspace-wide count of thinking entries across all symbols. Used as a fallback signal when prior_thinking finds nothing on the queried symbols.

Single ledger-tree walk. (Was: a per-qname symbol lookup plus a per-symbol ledger read — quadratic on big repos, and this function runs exactly when nothing matched, i.e. on the workspace-wide slow path. Plan T t-007 finding.)