Spec: nisse-review (Part R) before nisse-ops

A review agent comes second: it reads every ready PR in the repositories
it can see and discusses its points on the PR, never changing code.

- Architecture Part R: duty and items (R1), rounds capped and reset by
  anyone else commenting (R2), read-only reach bound to the item's
  repository, no approvals, no build VM for now (R3), peers (R4), local
  model with ask_expert, no Matrix room for now, own identity (R5).
- D5 and L11: a peer's review is constructive criticism, answered point by
  point; never an instruction, approval or go-ahead; nisse-dev doesn't
  wait for it before asking to merge.
- Part Q: letting nisse-review approve a limited subset of PRs.
- Development Plan: Phase 7 is nisse-core and nisse-review (M7.2-M7.6);
  nisse-ops moves to Phase 8 (M8.1-M8.5), with the MCP decisions so far.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01J5Utyfzw7gF7UhjRDEtjTk

nisse-core/README.md

@@ -19,4 +19,4 @@ never imports an agent.
   (`nisse-dev`'s are in `nisse_dev.loop.actions`).
 
 The loop is still `nisse-dev`'s, until `nisse-ops` has one to share it with
-(Development Plan M7.1).
+(Development Plan M7.2).