[osipovartem]

Summary

• Add an opt-in local scalar UDF hook that creates one invocation object when a physical scalar expression is built.
• Keep the registered UDF for metadata/coercion while invoking the physical instance for batch execution.
• Preserve the instance across physical-expression rewrites and forward the hook through aliases.

Motivation

Rustice SEQ functions need state shared across Arrow batches in one query but reset for the next query or view execution. A logical UDF instance can survive in saved plans; batch-local state resets too early.

Validation

• datafusion-physical-expr: 1610 passed, 2 ignored (full library suite).
• Focused physical-instance and alias tests pass.
• cargo fmt --check, clippy -p datafusion-physical-expr --lib --locked, and git diff --check pass.
• Independent read-only review: approved, no blocking findings.

Scope

This is intentionally a fork-local API. The stable-ABI FFI UDF wrapper does not forward this new hook; plan clones share the same invocation object. Ordinary UDFs retain their existing Arc and do not pay an extra per-batch branch.

CI context

The fork CI currently has unrelated failures outside this three-file diff: CLI integration cannot pull its MinIO image; an existing CSV diagnostic test compares a backtrace-bearing error string; Taplo reports the unchanged datafusion/datasource/Cargo.toml; generated function docs are stale on the base branch. The targeted datafusion-physical-expr suite (1610 passed, 2 ignored), local Rustice integration suite (3850/3850), formatting, and Clippy checks passed. The fork-only FFI limitation remains documented above.