chore(fleet): update ruff to >=0.16.3 and mypy to >=2.3.1

Applies dependabot #285 and #284 locally so the commits stay datascry-authored.
Resolves to ruff 0.16.4 and mypy 2.3.1 in the lockfile.

fleet already declares an explicit `select`, so ruff 0.16's wider defaults don't
reach it — the gate is clean with no code changes: ruff check, ruff format
--check, mypy --strict and 37 tests at 97.95% coverage all pass.

Author: datascry

fleet/pyproject.toml

@@ -12,8 +12,8 @@ skulk = "skulk.cli:main"
 dev = [
   "pytest>=9.1.1",
   "pytest-cov>=7.1.0",
-  "mypy>=2.3.0",
-  "ruff>=0.15.21",
+  "mypy>=2.3.1",
+  "ruff>=0.16.3",
 ]
 
 [build-system]