tooling: Enable ruff preview rules E203, E302, and E303.

Closes #400.

These three pycodestyle rules are in preview in ruff 0.11.6 and were not
active because of explicit-preview-rules = true. Add them to the explicit
select list and auto-fix the 11 existing violations across the codebase:

  E203 — whitespace before ':' (catches `else :`, `if x :`, etc.)
  E302 — expected 2 blank lines before function/class definition
  E303 — too many blank lines inside a block

E203 was spotted in PR #399 (Aline's tamagotchi example) and E302/E303
in PR #376 (Kaan's spirit level) — both were caught manually because
ruff did not flag them.

Author: nedseb

lib/apds9960/examples/light_theremin.py

@@ -66,7 +66,6 @@
             # Map the light range to an index in our note array (0 to 14)
             note_index = (clamped_light - MIN_LIGHT) * (TOTAL_NOTES - 1) // range_light
 
-
             # Fetch the perfect harmonic frequency
             freq = PENTATONIC_NOTES[note_index]
 
@@ -77,7 +76,6 @@
                 print("Light: {} | Note: {} | Freq: {} Hz".format(light_level, note_index, freq), end="\r")
                 last_freq = freq
 
-
         sleep_ms(20)
 
 except KeyboardInterrupt:

lib/mcp23009e/examples/i2c_scan.py

@@ -13,7 +13,6 @@
 reset.value(1)
 
 
-
 print("=" * 60)
 print("Scanner I2C - Recherche des périphériques")
 print("=" * 60)

lib/steami_config/steami_config/device.py

@@ -12,6 +12,7 @@
 # Reverse map: short key -> sensor name.
 _KEY_SENSORS = {v: k for k, v in _SENSOR_KEYS.items()}
 
+
 class SteamiConfig(object):
     """Persistent configuration stored in the DAPLink F103 config zone.
 
@@ -239,7 +240,6 @@ def get_accelerometer_calibration(self):
             "oz": cal.get("oz", 0.0),
         }
 
-
     def apply_accelerometer_calibration(self, ism330dl_instance):
         """Apply stored accelerometer calibration to an ISM330DL instance."""
         if type(ism330dl_instance).__name__.lower() != "ism330dl":

lib/steami_screen/steami_screen/device.py

@@ -40,6 +40,7 @@
 
 # --- Cardinal position names ---
 
+
 class Screen:
     """High-level wrapper around a raw display backend."""
 
@@ -196,7 +197,6 @@ def bar(self, val, max_val=100, y_offset=0, color=LIGHT):
         if fill_w > 0:
             self._fill_rect(bx, by, fill_w, bar_h, color)
 
-
     def gauge(self, val, min_val=0, max_val=100, color=LIGHT):
         """Draw a circular arc gauge (270 deg, gap at bottom).
 

lib/wsen-pads/examples/altitude.py

@@ -10,6 +10,7 @@
 
 sensor = WSEN_PADS(i2c)
 
+
 def pressure_to_altitude(p):
     return 44330 * (1 - (p / SEA_LEVEL_PRESSURE) ** EXPONENT)
 

lib/wsen-pads/examples/pressure_trend.py

@@ -15,6 +15,7 @@
 MAX_VALUES = 10
 THRESHOLD = 0.5  # sensitivity (hPa)
 
+
 def get_trend(values):
     if len(values) < 2:
         return "N/A"

lib/wsen-pads/examples/temp_pressure_display.py

@@ -15,6 +15,7 @@
 i2c = I2C(1)
 sensor = WSEN_PADS(i2c)
 
+
 def bar_graph(value, vmin, vmax, width=20):
     # Clamp value
     if value < vmin:

pyproject.toml

@@ -48,10 +48,13 @@ select = [
   "C90",    # McCabe cyclomatic complexity
   "DTZ",    # flake8-datetimez
   "E",      # pycodestyle
+  "E203",   # (preview) whitespace before ':', ';', or ','
   "E225",   # (preview) missing whitespace around operator
   "E261",   # (preview) at least two spaces before inline comment
   "E262",   # (preview) inline comment must start with '# '
   "E265",   # (preview) block comment must start with '# '
+  "E302",   # (preview) expected 2 blank lines before function/class definition
+  "E303",   # (preview) too many blank lines
   "EXE",    # flake8-executable
   "F",      # Pyflakes
   "G",      # flake8-logging-format

tests/conftest.py

@@ -23,7 +23,6 @@ def pytest_addoption(parser):
     )
 
 
-
 def pytest_collection_modifyitems(config, items):
     port = config.getoption("--port")
     driver = config.getoption("--driver")