chore(ci): add ruff and mypy, wire them into CI

Back the shipped py.typed promise with an enforced type check and a linter:

- Add ruff + mypy (+ types-requests) to the dev extras and dev requirements,
  with [tool.ruff]/[tool.mypy] config in pyproject.toml (mypy checks the
  package, not the tests).
- Add a lint job to the Forgejo workflow running ruff check + mypy.
- Fix the issues this surfaced: type FileLock.fd as TextIO | None, add a
  targeted type: ignore for the intentional socket.getaddrinfo monkeypatch,
  and drop an unused import.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

pyproject.toml

@@ -17,6 +17,9 @@ dependencies = [
 [project.optional-dependencies]
 dev = [
     "pytest>=7.4",
+    "ruff>=0.6",
+    "mypy>=1.11",
+    "types-requests",
 ]
 
 [project.scripts]
@@ -27,3 +30,13 @@ where = ["src"]
 
 [tool.setuptools.package-data]
 llamacppctl = ["py.typed"]
+
+[tool.ruff]
+target-version = "py310"
+line-length = 100
+
+[tool.mypy]
+python_version = "3.10"
+files = ["src/llamacppctl"]
+warn_unused_ignores = true
+warn_redundant_casts = true