Fixes from the first live session of the new loop

Found live on 2026-10-07 (bring-up on nisse-testing-operator/nisse-bringup,
Opus as driver):

- The driver's prose nudge went into the system prompt, so the retry ended
  on the model's own reply. Opus 5.5 refuses that ("does not support
  assistant message prefill. The conversation must end with a user
  message"). The nudge is now a harness fact in the conversation. The
  delegation harness's prose path did the same and is fixed likewise.
- A helper's first request ended with its own delegation_started event,
  rendered as an assistant message: every delegation would have failed on
  Opus. The helper now sees it as the harness handing over its task.
- model_contract checks that every request ends on the user's side, so
  scripted tests catch this from now on (each fix is mutation-checked).
- `status` (and `details`) in an item's thread were taken as replies: they
  woke the driver and cancelled a bug's countdown. They now answer at once
  and change nothing.
- The driver had no way to answer a remark without changing the item, so it
  answered in prose. Every run woken by a message (or a review comment) now
  offers `reply`, which answers where asked and returns to the very wait
  that was interrupted.

Also: scripts/bringup-repo.sh makes the bring-up's test repository
(make_repo/delete_repo, split out of fresh_repo), and made repositories get
the agent's labels (bug, discuss, design).

Tests: test_loop_live_fixes.py (one per finding); the walk sends `status`
into threads (status_changes_nothing) and its scripted driver sometimes
answers remarks with reply.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPQ14L3LikyefCMFBqEbKE

nisse-dev/tests/test_loop_properties.py

@@ -83,8 +83,15 @@ class PolicyModel:
             return [call("ask_human", question=f"question {self.n}?")]
         if roll < 0.12:
             return [ToolCall(call_id=f"p{self.n}", tool="nonsense", arguments={})]
-        if "reply" in offered and "propose_work" not in offered:
+        if "reply" in offered and not offered & {
+            "propose_work",
+            "restate",
+            "ask_human",
+            "start_milestone",
+        }:
             return [call("reply", text=f"because {self.n}")]  # a question run
+        if "reply" in offered and "propose_work" not in offered and roll < 0.2:
+            return [call("reply", text=f"noted {self.n}")]  # a remark answered
         if "reply" in offered:  # a conversation: talk, or propose work
             if self.rng.random() < 0.1:
                 return [
@@ -258,6 +265,7 @@ class Walk:
         if item and loop:
             weights.update({"go": 3, "answer": 2, "abandon": 1, "go-stale": 1})
             weights.update({"plain-yes": 2, "wait": 2, "question": 2})
+            weights.update({"status-here": 1})
             if loop.new_project:
                 weights.update({"done": 2})
             if item.scope != "general":  # conversations aren't named by number
@@ -273,6 +281,18 @@ class Walk:
         elif action == "done" and loop:
             # The operator says a new project is ready; no entry was added.
             self.transport.receive(DON, "done", thread=loop.thread)
+        elif action == "status-here" and loop:
+            # L5: a command about the item, not a reply: nothing changes,
+            # not even a countdown.
+            before = (item.position, loop.wait, loop.rev, loop.grace_until)
+            self.transport.receive(DON, "status", thread=loop.thread)
+            after_item = self.world["store"].work_item(item.id)
+            after = loop_of(after_item)
+            now = (after_item.position, after.wait, after.rev, after.grace_until)
+            assert now == before, (
+                f"status_changes_nothing: {before} -> {now}: "
+                f"seed {self.seed}, steps {self.steps}"
+            )
         elif action == "question" and loop:
             # L5: a question never changes the item it's asked about.
             before = (item.position, loop.wait, loop.rev, loop.pr, loop.branch)