fix(deps): move off the yanked spin 0.9.8 (#48)

cargo audit reports spin 0.9.8 as yanked. Bump the workspace pin to
0.10 (resolves to 0.10.1); no source changes were needed.

Supersedes #30, which carried the same one-line bump but had drifted
into a Cargo.lock conflict against main.


Claude-Session: https://claude.ai/code/session_016QSCkKnxDjqU49NVVpWMK5

Author: ruvnet

Cargo.lock

@@ -69,7 +69,7 @@ sha2 = { version = "0.10", default-features = false }
 sha3 = { version = "0.10", default-features = false }
 subtle = { version = "2.6", default-features = false }
 xxhash-rust = { version = "0.8", default-features = false, features = ["xxh3"] }
-spin = { version = "0.9", default-features = false }
+spin = { version = "0.10", default-features = false }
 bitflags = { version = "2", default-features = false }
 
 # Testing