refactor: prune orphaned attic modules and standardize project configurations

- Move orphaned modules (data_segment.py, contour_models.py, marching_squares.py) to attic/.
- Standardize local settings logic, serial port parameters, and graph view plots.
- Update pyproject.toml pyside6-project dependencies and configure gitignore.

pyproject.toml

@@ -49,7 +49,7 @@ files = [
     "src/pygui/ISC/Tabs/qmldir",
     "src/pygui/__main__.py",
     "src/pygui/backend/contour_models.py",
-    "src/pygui/backend/crypto_helper.py",
+    "src/pygui/backend/crypto/crypto_helper.py",
     "src/pygui/backend/csv_file_metadata.py",
     "src/pygui/backend/data_model.py",
     "src/pygui/backend/data_segment.py",
@@ -103,7 +103,7 @@ environments = [
 # ===== Ruff Linter and Formatter =====
 [tool.ruff]
 target-version = "py311"
-line-length = 100
+line-length = 125
 
 [tool.ruff.lint]
 select = [
@@ -113,7 +113,11 @@ select = [
     "I",   # isort (import sorting)
     "N",   # pep8-naming
 ]
-ignore = []
+ignore = [
+    "N802",  # Function name should be lowercase (standard for Qt Slots and Properties)
+    "N815",  # Class attribute should not be mixedCase (standard for Qt Properties and Signals)
+    "E702",  # Multiple statements on one line (semicolon, standard for inline Qt property setters with self.update())
+]
 
 # ===== Mypy Static Type Checker =====
 [tool.mypy]