Conversation on the new loop (M2.7)

- Questions never change state (L5, #77): a message ending in "?" to a
  waiting project item starts a question run (reply and look-only tools,
  an instruction to change nothing), and the item goes back to the very
  wait it was in: a restatement up stays up and a go binds to it; the
  agent's own question stays open.
- Explanations: a restatement gives its reasons and the main alternative;
  a revision says what changed (restate(changed), sent back without it);
  a milestone's summary says what was done, verified and left open.
- Progress in prose (#42): the driver's and a helper's own words for a
  turn are posted, trimmed, at most once a minute per item; `details`
  shows the last tool calls; a message arriving mid-run is acknowledged at
  once ("Noted; ...").
- CI: the e2e job's comments and the plan no longer claim a newer push
  cancels the run it supersedes (Gitea here doesn't); the concurrency
  block goes.

Tests: conversation unit tests (questions in a go-ahead and an answer wait,
an unanswerable question, revisions, progress rate and trimming, details,
mid-run notes), the helper's progress, the walk asking questions in every
state with a questions_change_nothing property (routing questions the old
way fails 32 of 48 seeds), and an e2e question while a restatement is up.

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

docs/Development-Plan.md

@@ -76,8 +76,9 @@ Only `nisse-dev` has real code; `nisse-core` and `nisse-ops` are placeholders.
 - **The end-to-end test runs on every PR** (M1.6): the real agent, every role on a
   local model (so it costs nothing per call), a repository of the run's own and a
   real build host, driven by a scripted operator. CI runs it as its own job on pull
-  requests, cancelling a run a newer push supersedes. Locally only the tests being
-  written (`-k`) or diagnosed (`--lf`); `scripts/e2e.sh` reports what a run spent. Manual
+  requests, after the checks pass. There is one runner, and a run a newer push
+  supersedes has to be cancelled by hand. Locally only the tests being written
+  (`-k`) or diagnosed (`--lf`); `scripts/e2e.sh` reports what a run spent. Manual
   live runs are for the new loop's first runs and phase ends. Findings are filed as
   issues and either fixed before moving on or deliberately deferred.
 - **The Quint models move with the loop:** `orchestrator.qnt` while `control.py`
@@ -240,8 +241,19 @@ deletes afterwards.
 - Evaluation capture: delegations, `ask_expert` and the reader's verdicts.
 - Deferred: the context-won't-fit trigger (L6); the action classifier (M3.2).
 
-**M2.7 Conversation.** *Pre-approved.* Explanations, progress in prose, asking
-mid-work (L5, #42, #77).
+**M2.7 Conversation.** *Pre-approved.* **Done** (this PR). Explanations, progress
+in prose, asking mid-work (L5, #42, #77).
+- Questions never change state: a message ending in `?` to a waiting project item
+  is answered in a question run (`reply` and look-only tools), and the item goes
+  back to the very wait it was in, so a restatement up stays up and a go binds to
+  it.
+- A restatement gives its reasons and the main alternative; a revision says what
+  changed (`restate(changed)`, sent back without it).
+- Progress: the driver's and a helper's own words for a turn are posted, trimmed,
+  at most once a minute per item; `details` shows the last tool calls. A message
+  arriving mid-run is acknowledged at once.
+- Deferred: streaming (#42); the question property in `specs/loop.qnt` (the walk
+  checks it against the code).
 
 **M1.4 Projects** (D8). *Pre-approved.* **Done** (this PR).
 - The project entry in configuration: repository, default branch, build VM, label