build(fuzz): require tines-core 1 and check the fuzz crate in ci.sh

fuzz/Cargo.toml still required tines-core 0.3.0, so since the 1.0.0
version bump `cargo fuzz run node` failed version selection (B6). The
requirement is now "1" and the lock is regenerated.

scripts/ci.sh now runs rustfmt and clippy (all targets, -D warnings) on
the out-of-workspace fuzz crate on the pinned stable toolchain, so it
can't silently stop building again. fuzz/.gitignore ignores target,
artifacts and coverage.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

fuzz/Cargo.lock

@@ -277,7 +277,7 @@ dependencies = [
 
 [[package]]
 name = "tines-core"
-version = "0.3.0"
+version = "1.0.0"
 dependencies = [
  "blake2",
  "heapless",