Add agent rehearsal harness, findings, and per-run evidence for split-loop-with-lambda

Six scripted pi sub-agent runs (3 tool regimes × 2 models) rehearsed the
exercise; deterministic gate = solution test + approved file. Key results:
mandated CLI triples cost on the strong model (4:06 vs 0:39, PASS both);
weak model fails only under the mandate (A+Q), passes when free or optional.
Drift documented with code: scorer.updateSelection left inside the extracted
method (A+Q, C+Q). Harness in tools/rehearse; summary in
rehearsal-findings.md; per-run evidence in rehearsal-runs/; cheat sheet in
rehearse-with-agent.md corrected (lambda-typed parameters unsupported).

ideas/split-loop-with-lambda/exercise/rehearsal-runs/B/measure.txt

@@ -0,0 +1,35 @@
+--- Run B ---
+session file: /tmp/rehearsal/runs/B/session/2026-09-27T14-53-00-499Z_01a0e35a-e6d3-70ca-b02c-6d99534cf397.jsonl
+model:                z-ai/glm-5.3-flash
+session span:         39.2 s
+assistant messages:   10
+tool calls:           10 total
+  bash                     5
+  edit                     4
+  read                     1
+tokens input:         21722
+tokens output:        4361
+tokens cacheRead:     33984
+tokens cacheWrite:    0
+tokens reasoning:     2129
+tokens TOTAL (sum):   62196
+--- /usr/bin/time -v (wall clock + max RSS) ---
+	Elapsed (wall clock) time (h:mm:ss or m:ss): 0:39.35
+	Maximum resident set size (kbytes): 249312
+	Exit status: 0
+--- pi stdout (last 15 lines) ---
+            Boolean lookupWeather = dayOffsetToWeather.apply(daysForward);
+            expectedWeather.add(lookupWeather);
+        }
+        return expectedWeather;
+    }
+}
+```
+
+**Diff summary** (relative to the original):
+1. Added import `java.util.function.LongFunction`.
+2. The scorer-dependent code (`scorer.updateSelection()` + `scorer.lookupWeather(daysForward)`) was extracted into a lambda, now passed in as `dayOffsetToWeather` (`LongFunction<Boolean>`); the invocation site (`dayOffsetToWeather.apply(daysForward)`) stayed in the loop.
+3. The weather-collection loop (with `interestingDates`) moved into new private method `collectExpectedWeather(LongFunction<Boolean> dayOffsetToWeather)` returning `List<Boolean>`.
+4. Signature changed from `longRangeForecast(String quarter)` to `longRangeForecast(LongFunction<Boolean> dayOffsetToWeather)`; the `String quarter` parameter and its `Q1`/`Q4` block were removed, and a public no-arg overload was added that delegates and wraps the `scorer` field in a lambda.
+
+**Note:** the test call site in `src/test/java/codingdojo/LongRangeForecastsTest.java` was updated (`longRangeForecast(quarter)` → `longRangeForecast()`) so the project still compiles after the signature change.