Function verify_no_overhead_source 

pub fn verify_no_overhead_source(source: &str) -> Result<(), String>

Verify that a LogicAffeine program has no interpretive overhead.

Checks the AST for patterns that indicate unresolved interpreter dispatch:

• Inspect on CStmt/CExpr/CVal variants
• References to Core constructor types (CInt, CShow, etc.)
• Environment lookups on literal strings