chore: clear the rustc 1.96 clippy lints that fail cargo xtask ci

Unrelated to the #2135 security fix in the commit before this one: both lines
predate this branch and are rustc/clippy 1.96 lint churn. `cargo clippy
--workspace --all-targets` only warns about them, but `cargo xtask ci` runs it
with `-D warnings` (xtask/src/main.rs), so the gate fails before any test runs.

- `clippy::nonminimal_bool` in `slide_overlay::shadow` (reported twice, two
  overlapping suggestions on the one expression): `!(A && B) || !C || !D` is
  `!(A && B && C && D)` by De Morgan, which is what the line now says. The
  operands are pure float comparisons and `is_finite` guards with no side
  effects, so this is an exact rewrite — a NaN or infinite `mx0`/`my0` still
  makes `shadow` return without drawing, as before. (Clippy's second suggestion
  drops the `my0.is_finite()` term and is *not* equivalent; it is not used.)
- `clippy::drop_non_drop` on `drop(write)` in
  `same_folder_as_original_refuses_photos_without_a_folder`. The line is not
  dead: `write` is a closure holding a mutable borrow of `written`, and the
  `drop` ended that borrow so the next assertion could read it. The closure now
  lives in a block of its own instead, which ends the borrow at the brace
  rather than relying on `drop` of a non-`Drop` type. Every assertion of the
  test is unchanged.

Co-Authored-By: Claude <[email protected]>

crates/engine/src/slide_overlay.rs

@@ -903,7 +903,7 @@ fn shadow(img: &mut Rgba8, tl: &crate::text::TextLayout, x: f64, y: f64, sigma:
     let my0 = (y - pad).floor().max(-pad);
     let mx1 = (x + tl.width as f64 + pad).ceil().min(iw + pad);
     let my1 = (y + tl.height as f64 + pad).ceil().min(ih + pad);
-    if !(mx1 > mx0 && my1 > my0) || !mx0.is_finite() || !my0.is_finite() {
+    if !(mx1 > mx0 && my1 > my0 && mx0.is_finite() && my0.is_finite()) {
         return;
     }
     let (w, h) = ((mx1 - mx0) as usize, (my1 - my0) as usize);

crates/engine/src/tests_export.rs

@@ -1024,21 +1024,24 @@ fn same_folder_as_original_refuses_photos_without_a_folder() {
     let mut s = Session::with_demo();
     let ids: Vec<_> = s.catalog.photos().take(2).map(|p| p.id).collect();
     let mut written = Vec::new();
-    let mut write = |p: &str, _: &[u8]| -> Result<(), String> {
-        written.push(p.to_string());
-        Ok(())
+    // the writer lives in a block of its own, so its borrow of `written` has ended by the time
+    // the assertion below reads it
+    let files = {
+        let mut write = |p: &str, _: &[u8]| -> Result<(), String> {
+            written.push(p.to_string());
+            Ok(())
+        };
+        let err = crate::export::export_batch(&mut s, &ids, &o, &to, &mut write, &|_| false).unwrap_err();
+        assert!(err.contains("no folder on disk"), "{err}");
+        // without stopping: one error per photo, nothing written
+        let items = crate::export::prepare_batch(&mut s, &ids, &o).unwrap();
+        crate::export::run_batch(items, &o, &to, &mut write, &|_| false, false, &mut |_, _| true).unwrap()
     };
-    let err = crate::export::export_batch(&mut s, &ids, &o, &to, &mut write, &|_| false).unwrap_err();
-    assert!(err.contains("no folder on disk"), "{err}");
-    // without stopping: one error per photo, nothing written
-    let items = crate::export::prepare_batch(&mut s, &ids, &o).unwrap();
-    let files = crate::export::run_batch(items, &o, &to, &mut write, &|_| false, false, &mut |_, _| true).unwrap();
     assert_eq!(files.len(), 2);
     for (f, id) in files.iter().zip(&ids) {
         assert_eq!(f["photo"], id.0, "{f}");
         assert!(f["error"].as_str().unwrap().contains("no folder on disk"), "{f}");
     }
-    drop(write);
     assert!(written.is_empty(), "{written:?}");
 
     // a photo on disk whose folder is gone (moved, an unplugged drive)