fix(wasm): remove spurious i32.const from uncompiled assignment placeholders

Undcompiled map/record/unrecognized assignments emitted (i32.const 1)
placeholders that left values on the WASM stack. Combined with
the default return i32.const 1 at end of function, this caused
type mismatch errors (expected [], got [i32, i32] or [i32]).

Fix: make uncompiled assignments emit comment-only output with
no stack effect. Scalar assignments already work correctly since
emitExpr feeds into global.set which consumes the value.

Closes #9 WASM E2E portion — parser fix for precondition:/postcondition:
keyword handling still needed.

compiler/src/generators/wasm.ts

@@ -357,18 +357,16 @@ function emitAssignment(
     const keyExpr = mapAssign[2];
     // For now: map_set(map_handle, key_handle, value_handle)
     // This needs boxing; simplified version just marks as stub
-    return `;; Map assignment not yet compiled: ${target} := ${expr}\n` +
-           `    (i32.const 1)`;
+    return `;; Map assignment not yet compiled: ${target} := ${expr}`;
   }
 
   // Record field assignment: accounts[id].field := expr
   const recordAssign = target.match(/^(\w+)\[(.+)\]\.(\w+)$/);
   if (recordAssign && maps.has(recordAssign[1])) {
-    return `;; Record field assignment not yet compiled: ${target} := ${expr}\n` +
-           `    (i32.const 1)`;
+    return `;; Record field assignment not yet compiled: ${target} := ${expr}`;
   }
 
-  return `;; Unrecognized assignment target: ${target}\n    (i32.const 1)`;
+  return `;; Unrecognized assignment target: ${target}`;
 }
 
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