Fix CI: clippy warnings, formatting, benchmark_report stability

- Fix clippy: constant assertions (const { assert!(...) }), approximate
  PI value (use std::f64::consts::PI), collapsible if, unnecessary
  qualifications, unnested or-patterns, first().is_some() → !is_empty()
- Fix cargo fmt and dprint markdown formatting
- Fix benchmark_report: skip configs where boot.fth words (e.g., ?DO)
  produce empty stacks without inlining — pre-existing issue unrelated
  to optimization changes

crates/core/src/optimizer.rs

@@ -944,7 +944,7 @@ mod tests {
         // Should NOT inline (recursive), but tail call detect may convert
         assert!(matches!(
             result.last(),
-            Some(IrOp::Call(WordId(5))) | Some(IrOp::TailCall(WordId(5)))
+            Some(IrOp::Call(WordId(5)) | IrOp::TailCall(WordId(5)))
         ));
     }