Rewrite the lens to one the fixture did not draw (L1 c3.s1.f1)

The illegal-transition pin rewrote the recorded lens to Numen, but its
fixture draws under uniform weights with a random world id, so about one
run in eight the lens was already Numen and assert_ne! failed. The rewrite
now picks Patina when the recorded lens is Numen and Numen otherwise, so
the lens rewrite always differs from the row.

Measured: at ef64008, 3 of 40 runs failed at controllers.rs:10230 with the
recorded lens Numen; after the change, 120 of 120 runs pass.

Test-only; no production code changes.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

crates/ghostlight/src/controllers.rs

@@ -10136,7 +10136,8 @@ mod tests {
     }
 
     /// Row to row, a session is whole: from a persisted in-flight checkpoint,
-    /// a next checkpoint that differs only in the lens, only in the text (with
+    /// a next checkpoint that differs only in the lens (always another lens
+    /// than the recorded one), only in the text (with
     /// its invocation prepared under that text, so integrity passes and the
     /// refusal is progression's), or only in the ancestry is refused by the
     /// real store as an illegal transition. The unchanged checkpoint is
@@ -10218,7 +10219,15 @@ mod tests {
                 invocation,
             }
         };
-        let lens = rewrite(&|session| session.lens = Lens::Numen);
+        // Another lens than the one the fixture drew, whichever that was: the
+        // fixture draws under uniform weights, so no fixed lens is safe.
+        let lens = rewrite(&|session| {
+            session.lens = if session.lens == Lens::Numen {
+                Lens::Patina
+            } else {
+                Lens::Numen
+            }
+        });
         let text = with_texts(
             &checkpoint,
             "text a later build wrote",