Add editor tooling to dev dependencies

flake8, autopep8, importmagic, epc, and jedi so that Spacemacs
finds them in the project venv (PEP 668 blocks system-wide installs).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Technologicat

pyproject.toml

@@ -47,6 +47,15 @@ classifiers = [
 [project.urls]
 Repository = "https://github.com/Technologicat/unpythonic"
 
+[dependency-groups]
+dev = [
+    "flake8",
+    "autopep8",
+    "importmagic",
+    "epc",
+    "jedi>=0.19.2",
+]
+
 [build-system]
 requires = ["pdm-backend"]
 build-backend = "pdm.backend"