Answer where asked, wait on a merge, and let the driver title PRs

From the new loop's first live run (sandbox #255, PR #256):
- A question asked on the PR is answered on the PR (an inline one quoted
  with its file and line, since the API can't reply in its thread), with
  a pointer in the item's Matrix thread; one asked in Matrix stays there.
- wait_for_review: when a review needs no change, or only the operator's
  merge is left, the item waits on the merge instead of on an answer.
- finish_milestone takes the PR's title from the driver.
The e2e test's merge waits out Gitea's brief 'try again later' after a
push.

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

nisse-dev/src/nisse_dev/loop/items.py

@@ -37,6 +37,12 @@ class Loop:
     comments: int = 0  # the last PR conversation comment taken (L8)
     notes: tuple[str, ...] = ()  # review notes taken (#69)
     fixes: int = 0  # review fixes pushed, for follow-up branch names
+    # Where the operator last spoke (D5: answer where asked): "" for the
+    # Matrix thread, or the PR it came from, with the inline location and a
+    # little of what they said, for quoting.
+    asked_on_pr: int = 0
+    asked_where: str = ""
+    asked_text: str = ""
 
     def to_data(self) -> dict[str, Any]:
         return asdict(self)