fix(display): routine rotation log lines are DEBUG (30% fewer journal lines) (#693)

"Processing mode", "display() returned False" and "No content to display" repeated what "Switching to mode" already logs on every rotation; they are now DEBUG. On ledpi this cut the display's journal lines by about 30%; the measured SD-write saving is small (within noise).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -303,6 +303,14 @@ read any of them:
 
 ### Fixes
 
+- Quieter routine logging. Every rotation logged each mode twice
+  ("Switching to mode", then "Processing mode"), and a mode with nothing to
+  show added "display() returned False" and "No content to display". Those
+  three repeats are now DEBUG; "Switching to mode" stays INFO, and `--debug`
+  shows the rest. On ledpi this cut the display's journal lines by about 30%
+  (~105 to ~75 per 5 minutes). Each stored line costs roughly 9 KB of SD-card
+  writes through the persistent journal (display at INFO vs WARNING: about
+  190 KiB/min apart), so the saving is real but small.
 - Reinstalling a plugin by its registry id when it is installed under its
   manifest id (`weather` in `ledmatrix-weather/`) no longer deletes it when
   the install then fails. The safety copy was taken of `weather/`, which did

src/display_controller.py

@@ -2495,7 +2495,11 @@ class DisplayController:
 
                 manager_to_display = None
                 
-                logger.info("Processing mode: %s (%d available)", active_mode, len(self.available_modes))
+                # DEBUG, not INFO: "Switching to mode" already logged this mode. Every
+                # routine rotation line lands in the persistent journal, and on an SD
+                # card each one costs far more than its bytes: measured on ledpi, about
+                # 9 KB of card writes per stored line.
+                logger.debug("Processing mode: %s (%d available)", active_mode, len(self.available_modes))
                 logger.debug("Loaded plugin modes: %s", list(self.plugin_modes.keys()))
                 
                 # Handle plugin-based display modes
@@ -2623,7 +2627,7 @@ class DisplayController:
                         if isinstance(result, bool):
                             display_result = result
                             if not display_result:
-                                logger.info("Plugin %s display() returned False for mode %s", plugin_id, active_mode)
+                                logger.debug("Plugin %s display() returned False for mode %s", plugin_id, active_mode)
 
                         # Record success only when display() actually ran this
                         # frame -- a skipped frame (lock busy) held the last
@@ -2664,7 +2668,8 @@ class DisplayController:
                         self._advance_on_demand()
                         continue
                     else:
-                        logger.info("No content to display for %s, skipping to next mode", active_mode)
+                        # Routine (no live game right now): DEBUG, see "Processing mode" above.
+                        logger.debug("No content to display for %s, skipping to next mode", active_mode)
                         # Don't clear display when immediately moving to next mode - this causes black flashes
                         # The next mode will render immediately with force_clear=True, which is sufficient