Version 0.9.8

What's Changed

Bug fixes

• #74 — Fix NullPointerException in Block.code when from_json (or any other
  CodegenFallback expression) is used under whole-stage codegen with DataFlint
  instrumentation enabled. TimedWithCodegenExec now reports supportCodegen = false
  for wrapped operators that contain a CodegenFallback, mirroring Spark's own
  CollapseCodegenStages check that the transparent wrapper had been hiding.
• Compatible with Spark 3.0 → 4.x (uses TreeNode.find instead of the 3.2-only
  TreeNode.exists).

Hardening

• TimedExec.postRddId now overwrites the rddId metric instead of summing across
  re-executions of the same plan instance.
• TimedExec and TimedWithCodegenExec no longer compare equal — fixes a corner
  case in plan canonicalization / AQE plan reuse.
• executeCollect write-path is now bounds-safe; falls back to the standard path
  on unexpected plan shapes (vendor write commands, future Spark layouts).
• rddId metric switched from a "size" type to plain sum (no longer rendered as
  bytes — "12 B" — in the SparkUI).

Tests / CI

• New DataFlintCodegenFallbackSpec regression test for #74.
• pluginspark4 now runs version-portable specs against Spark 4.0.1 in CI.
• CI bumped to Java 17 (required by Spark 4); published jars stay Java 8 compatible.

Full Changelog: v0.9.7...v0.9.8