Decompose assertThat(a && b).isTrue() into separate assertions

[timtebeek]

• Resolves When migrating from JUnit to AssertJ, rely on context to provide better assertions #387 by adding DecomposeConjunctionAssertion, which splits assertThat(a && b).isTrue() into one assertThat(...).isTrue() statement per conjunct (recursively flattening nested &&), so each condition is asserted and reported on its own. This lets the existing dedicated-assertion recipes simplify each conjunct (e.g. isNotNull(), isGreaterThan(...)) and CollapseConsecutiveAssertThatStatements fuse same-subject results back into a single chain. isFalse() is deliberately left alone (negating a conjunction is not equivalent to negating each conjunct), and chains carrying .as()/.describedAs() descriptions are skipped. The recipe is registered first in the Assertj aggregate so its output flows through the rest of the pipeline. Covered by unit tests plus end-to-end tests in AssertJBestPracticesTest showing decomposition, the method-call side-effect-safe case, and collapse into a chain.