What

The InsertHeader SMT was dropping the fractional part of literal values when the parsed schema resolved to an integral type. For example, configuring value.literal: "2.0" produced a header with value 2 instead of 2.0. The configure method now detects this case and rewrites the schema and value to FLOAT32, FLOAT64, or Decimal so the original literal is preserved.

The behavior change is localized to connect/transforms/src/main/java/org/apache/kafka/connect/transforms/InsertHeader.java. When Values.parseString returns an integral-typed SchemaAndValue and the raw configured string contains a decimal point, the literal is re-encoded using BigDecimal, falling back to Decimal for values outside the range of float/double. All other inputs keep the previous behavior.

Why

Testing

Added InsertHeaderTest.insertionWithFloatHeader, which configures the SMT with the literal "2.0" and asserts that the resulting header carries a FLOAT32 value of 2.0f while preserving any pre-existing headers on the record. Existing tests continue to cover the integral and string literal paths, so non-numeric and integer literals are unchanged.

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JIRA: https://issues.apache.org/jira/browse/KAFKA-19717