Threads, commands and labels on the new loop (M2.3)

- Commands that name their item ("go #14", "abandon #14", "stop #14")
  apply to it wherever they're said; go, approve and abandon alone at top
  level are asked about (L5). stop is never taken as an answer.
- A plain-language reply to a restatement is read by GoAheadReader, one
  model call that agrees only on a clear yes; questions never reach it. The
  agent says "taking that as a go-ahead on rev-N" first, bound to the
  revision on screen at arrival (L3, L5, D1).
- Labels steer (D1): `bug` goes ahead after tuning.loop.bug_grace_s
  (default 600 s) unless the operator replies; `discuss` isn't offered
  restate until the operator has spoken; `bug`, `discuss` and `design` add
  to the driver's instructions. A restatement asks no questions.

Tests: label and command unit tests, the property walk with labelled
issues, plain yeses, named gos and time passing (grace_only_unanswered,
discuss_talks_first), and e2e tests for a bug proceeding after its grace
period and a plain-language go-ahead.

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/config.py

@@ -104,6 +104,13 @@ class ContextTuning:
     safety_margin: float = 0.1
 
 
+@dataclass(frozen=True)
+class LoopTuning:
+    # A restatement on a `bug` issue proceeds after this long without a
+    # reply (D1).
+    bug_grace_s: float = 600.0
+
+
 @dataclass(frozen=True)
 class Tuning:
     executor: ExecutorTuning = field(default_factory=ExecutorTuning)
@@ -111,6 +118,7 @@ class Tuning:
     delegation: DelegationTuning = field(default_factory=DelegationTuning)
     tools: ToolsTuning = field(default_factory=ToolsTuning)
     context: ContextTuning = field(default_factory=ContextTuning)
+    loop: LoopTuning = field(default_factory=LoopTuning)
 
 
 _TUNING_SECTIONS: dict[str, type] = {