Preserve SQL source spans for scalar UDF type errors

[osipovartem]

Summary

• Carry SQL invocation spans on logical scalar UDF calls through tree rewrites, type coercion, and simplification.
• Attach a structured diagnostic to UDF argument-type errors without replacing diagnostics supplied by inner calls or UDF implementations.
• Keep spans diagnostic-only so expression equality, hashing, and columnar execution are unchanged.

Verification

• cargo check --workspace --all-targets
• SQL integration test: repeated, reversed, nested, and multiline invalid UDF calls
• Optimizer tests: source span preservation and nested inner-error attribution
• Expr test: UDF-supplied diagnostic preservation
• Independent read-only review: approved, no blocking findings

Rustice will pin this revision and cover Snowflake 001044/42P13 wire positions in a separate PR.