v0.75.0

flow_stage workers are now visible in pi-web. A delegated worker used to be a session pi-web never mentioned — the operator watched the driving session go quiet.

Added

• flow_stage workers register themselves as pi-web subagents: the worker's session file carries the pi-web:subagent meta where pi-web's scanner looks for it (first data entry) and a terminal result when the run ends, so the worker appears in the session's Agents menu under profile flow-implement / flow-review — ✓ with its REPORT, ✗ failed, or interrupted. The row settles when the run ends; while it runs pi-web displays it as interrupted, because only pi-web's own sessions can prove liveness. Plain pi is unchanged, and a stamp that cannot write never breaks a worker.