Keep runs with different tuning apart in the report, and raise max_turns to 40

The report grouped runs by model, serving note and task version, so
runs made at different tuning were silently averaged together. Tuning
is now part of the key, and a tuning column shows how a row's settings
differ from today's defaults; it appears only when some row needs it.

tuning.executor.max_turns goes from 24 to 40. On the harder benchmark
tasks Haiku, the calibration ceiling, hit 24 on both refactor-rename
runs and both long-milestone runs, one of which had finished the work.
The cap guards against a model trying forever; it isn't a budget.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

nisse-dev.example.yaml

@@ -47,7 +47,7 @@ gitea:                                # B2
 # read at startup, so a change takes effect on the next restart.
 tuning:
   executor:
-    max_turns: 24            # model calls per milestone before it stops as capped
+    max_turns: 40            # model calls per milestone before it stops as capped
     failure_limit: 2         # consecutive failed commands before escalating (A12)
   expert:
     consult_budget: 3        # ask_expert calls per milestone (A14)