Rename split-loop-with-lambda to slice-with-lambda

The refactoring is now published as Slice on sammancoaching.org:
https://sammancoaching.org/refactorings/slice.html

- git mv ideas/split-loop-with-lambda -> ideas/slice-with-lambda
- rename learning-hour file and update frontmatter name
- update paths in tools/rehearse scripts and report title
- update prose: 'Split Loop with Lambda' -> 'Slice with Lambda'
  in learning hour, exercise READMEs, storyboard, solution comments
- link the published Slice refactoring from the pattern draft

ideas/slice-with-lambda/exercise/rehearsal-runs/B+Q/pi-stdout.txt

@@ -0,0 +1,15 @@
+All three steps are complete. The code compiles successfully. Here's a summary of the refactoring:
+
+---
+
+## Final Diff for `LongRangeForecasts.java`
+
+| Change | Description |
+|--------|-------------|
+| **Import** | Added `java.util.function.LongFunction` |
+| **New no-arg overload** | `longRangeForecast()` — wraps the scorer in a lambda and delegates to the parameterized version |
+| **Signature change** | `longRangeForecast(String quarter)` → `longRangeForecast(LongFunction<Boolean> dayOffsetToWeather)` — removed `quarter` param and its Q1/Q4 block |
+| **Lambda extraction** | Removed the internal `dayOffsetToWeather` lambda definition; it's now passed as a method parameter |
+| **New helper method** | `collectExpectedWeather(List<Instant>, LongFunction<Boolean>)` — extracted weather-collection loop, receives the dependency-injected lambda |
+
+The key outcome is that `Scorer` is no longer directly invoked inside `longRangeForecast`. Its behavior is injected via the `LongFunction<Boolean>` parameter, making the method testable and decoupled from the external dependency.