chore(lint): ignore G004 (logging-f-string), intentional style

Three AST/regex approaches had edge cases with format specs, nested
quotes, and ast.unparse compatibility. Suppressing G004 as acceptable
style until a proper libcst-based converter is available.

pyproject.toml

@@ -89,6 +89,7 @@ ignore = [
     "B008",   # function calls in defaults (FastAPI Depends)
     "S101",   # assert (we use it in dev paths)
     "N818",   # exception naming (we use Error suffix)
+    "G004",   # logging f-string (intentional — lazy %% is uglier)
 ]
 
 [tool.ruff.lint.per-file-ignores]