parallel-pr-fanoutlisted

# Parallel PR fan-out Running N agents is the easy part. The batch succeeds or fails on two things decided *before* launch: whether any two agents can touch the same file, and whether each agent's brief carries the facts it cannot discover. Get the first wrong and the PRs conflict on arrival; get the second wrong and a confident agent ships a plausible fix to the wrong problem. ## Procedure 1. **Partition by file ownership, not by topic.** List every file each unit will touch — including the ones topics forget: the shared test file, the docs table that indexes scripts, the README section a change falsifies, the `.gitignore`. Two units sharing any file merge into one unit or run in sequence. State each agent's allowed file set explicitly and name the files it must NOT touch as "owned by parallel agents". File disjointness is necessary, not sufficient: a producer/consumer contract, a migration, a generated file and its source can couple units that share no path — check for those couplings before declaring merge order free. 2. **Write the brief an agent cannot reconstruct.** Findings with `file:line`, what was already ruled out, the repo's invariants that apply, and the exact verification commands. An agent without these ranks confidently wrong — and reads just as authoritative either way. 3. **Standard boilerplate, verbatim in every brief:** - branch from `origin/<integration branch>`, never the local one; - run the repo's full verifi