Covers the browser-client core: transcript building (text merging, event-to-entry mapping), browser-tool batches that capture failures without aborting, and the run driver's auto-resume across tool pauses, parking on approvals and unresolved tool calls, error propagation, and pass-through of app-specific events.

## Before writing SPEC.md files

Read https://raw.githubusercontent.com/brillout/sdd/refs/heads/main/sdd.md
