chore(deprecation): retarget the 35 deprecations to 3.8.0 and add a usage scan (#681)

Moves the 35 @deprecated markers from 3.7.0 (already shipped with them in
place) to 3.8.0, and adds scripts/plugin_api_usage.py plus the generated
docs/DEPRECATIONS_3.8.md: who still calls or overrides each deprecated
method across core, the monorepo and third-party plugins. Removes nothing.

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

src/display_manager.py

@@ -1320,7 +1320,7 @@ class DisplayManager:
         except Exception as e:
             logger.error(f"Error drawing text: {e}", exc_info=True)
 
-    @deprecated("3.7.0")
+    @deprecated("3.8.0")
     def draw_sun(self, x: int, y: int, size: int = 16):
         """Draw a sun icon using yellow circles and lines."""
         center = (x + size//2, y + size//2)
@@ -1341,7 +1341,7 @@ class DisplayManager:
             end_y = center[1] + ((radius + ray_length) * math.sin(rad))
             self.draw.line([start_x, start_y, end_x, end_y], fill=(255, 255, 0), width=2)
 
-    @deprecated("3.7.0")
+    @deprecated("3.8.0")
     def draw_cloud(self, x: int, y: int, size: int = 16, color=(200, 200, 200)):
         """Draw a cloud icon."""
         # Draw multiple circles to form a cloud shape
@@ -1349,7 +1349,7 @@ class DisplayManager:
         self.draw.ellipse([x+size//2, y+size//3, x+size//2+size//2, y+size//3+size//2], fill=color)
         self.draw.ellipse([x+size//3, y+size//6, x+size//3+size//2, y+size//6+size//2], fill=color)
 
-    @deprecated("3.7.0")
+    @deprecated("3.8.0")
     def draw_rain(self, x: int, y: int, size: int = 16):
         """Draw rain icon with cloud and droplets."""
         # Draw cloud
@@ -1364,7 +1364,7 @@ class DisplayManager:
             self.draw.line([drop_x, drop_y, drop_x, drop_y+drop_size], 
                           fill=drop_color, width=2)
 
-    @deprecated("3.7.0")
+    @deprecated("3.8.0")
     def draw_snow(self, x: int, y: int, size: int = 16):
         """Draw snow icon with cloud and snowflakes."""
         # Draw cloud
@@ -1485,7 +1485,7 @@ class DisplayManager:
         ]
         self.draw.polygon(bolt_points, fill=bolt_color)
 
-    @deprecated("3.7.0")
+    @deprecated("3.8.0")
     def draw_weather_icon(self, condition: str, x: int, y: int, size: int = 16) -> None:
         """Draw a weather icon based on the condition."""
         if condition.lower() in ['clear', 'sunny']:
@@ -1502,7 +1502,7 @@ class DisplayManager:
             self._draw_sun(x, y, size)
         # Note: No update_display() here - let the caller handle the update
 
-    @deprecated("3.7.0")
+    @deprecated("3.8.0")
     def draw_text_with_icons(self, text: str, icons: List[tuple] = None, x: int = None, y: int = None, 
                             color: tuple = (255, 255, 255)):
         """Draw text with weather icons at specified positions."""
@@ -1828,7 +1828,7 @@ class DisplayManager:
         if removed_count > 0:
             logger.debug(f"Cleaned up {removed_count} expired deferred updates")
 
-    @deprecated("3.7.0")
+    @deprecated("3.8.0")
     def get_scrolling_stats(self) -> dict:
         """Get current scrolling statistics for debugging."""
         return {