Index the is_error boolean from JSONL tool_result blocks into a new
column, replacing the old ERROR_PATS text-matching approach that
produced ~90% false positives. Bash exit code pattern kept as fallback.
Add sessions() as first-class entry point for session discovery with
project/time/branch filters. Extend summaries, workflows, failures,
subagents, fileHistory with the same opts vocabulary that search()
already had — no more pulling full datasets to filter client-side.