build: keep debug info in the test profile only, not release

[profile.release] debug = true forced full DWARF into release builds.
On ELF targets (the manylinux/musllinux wheels) the debug sections are
embedded in the .so (~160 MB, over PyPI's 100 MB file limit); MSVC emits
a sidecar .pdb instead and the apple/zig link path drops it, so only the
Linux wheels were bloated. Move debug=true to [profile.test] so cargo
still gets readable backtraces without fattening the release wheels.

Cargo.toml

@@ -17,9 +17,15 @@ categories = ["multimedia::images", "science"]
 
 [profile.test]
 inherits = "release"
+# Full debug info goes in the TEST profile only (readable cargo-test
+# backtraces). It must NOT be in the release profile: on ELF targets
+# (Linux/musl wheels) the DWARF gets embedded in the .so (~160 MB, over
+# PyPI's 100 MB limit) - MSVC puts it in a sidecar .pdb and the
+# apple/zig link path drops it, which is why only the Linux wheels were
+# bloated.
+debug = true
 
 [profile.release]
-debug = true
 
 [profile.dev.package.backtrace]
 opt-level = 3