fix(contract): clippy erasing_op in M1 test — drop the vacuous high-bit assertion (CI #439)

clippy::erasing_op on recipe_kernels.rs:1074: `m.0 & !0xFF` where m.0:u8 is always 0
(a u8 can't hold bits above 0xFF). The 'no stray high bits' guard was meaningless on a
u8; the real invariant (len() <= 8) is already asserted. Removed the tautological line.

https://claude.ai/code/session_01R9AWgFa65uPnLyS2my2d2R

Author: claude

crates/lance-graph-contract/src/recipe_kernels.rs

@@ -1069,10 +1069,10 @@ mod tests {
             distinct.len()
         );
 
-        // Every non-empty mask is within the 8-field basis (no stray high bits).
+        // Every mask is within the 8-field basis. (`u8` is structurally 8 bits, so
+        // the bound is on the populated-field count, not stray high bits.)
         for m in &masks {
-            assert_eq!(m.0 & !0xFF, 0);
-            assert!(m.len() <= 8);
+            assert!(m.len() <= 8, "mask exceeds the 8-field ThoughtField basis");
         }
     }