Emit floats an f32 can hold, and drop the format! that formats nothing

CI runs cargo fmt --check and clippy -D warnings, and this branch had
never been through either. Both would have failed it.

The bulk was the generated colour tables: eight significant figures where
an f32 carries about 7.2, so the eighth is noise that rounds away at
compile time and clippy's excessive_precision says so 109 times over.
Fixed in the generator rather than only in the file, so it stays fixed --
and the file is trimmed in place rather than re-derived, because
regenerating it needs a colour-science stack that has nothing to do with
the defect.

The format! in the composer is mine too, from extracting the rendering
tail: the braces in it were escaped because the text used to live inside a
larger template, and once extracted the escapes are noise and the call
formats nothing.

Also here, and clearly not mine: an unused import and a shadowed binding
in dr-gpu, and an unused import in a test. They are pre-existing --
clippy has been failing on master before this branch existed, on lints
like is_multiple_of that arrived with a toolchain rather than with
anyone's code. Fixed because CI cannot go green around them, and called
out because a merge commit is a bad place to quietly edit someone else's
crate.

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

core/dr-gpu/src/adjust.rs

@@ -1153,7 +1153,6 @@ mod tests {
     // asks the chain which of its operations are neighbourhood operations
     // rather than being told a list. Imported anonymously: nothing here names
     // the trait, only calls through it.
-    use dr_pipeline::Operation as _;
 
     use crate::Demosaicer;
 
@@ -1744,10 +1743,6 @@ mod tests {
         }));
         pass.set_film(Some(&tables));
 
-        // Cropped, so the render is against an output size that is not the
-        // source size — the case where a wrong dispatch or a wrong texture
-        // allocation would show up.
-        let (w, h) = g.output_size(32, 32);
         let shader = g.compose();
         // At 512 rather than the 32 this test used before the detail stage
         // existed, and the size is load-bearing twice over. A compositional