fix: narrow bare except blocks to specific exception types (#282)

Replace 6 bare `except:` blocks with targeted exception types:
- logo_downloader.py: OSError for file removal, (OSError, IOError) for font loading
- layout_manager.py: (ValueError, TypeError, KeyError, IndexError) for format string
- app.py: (OSError, ValueError) for CPU temp, (SubprocessError, OSError) for systemctl, (KeyError, TypeError, ValueError) for config parsing

Co-authored-by: 5ymb01 <5ymb01@users.noreply.github.com>
Co-authored-by: 5ymb01 <noreply@github.com>
Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

src/layout_manager.py

@@ -238,7 +238,7 @@ class LayoutManager:
         # Format the text
         try:
             text = format_str.format(value=value)
-        except:
+        except (ValueError, TypeError, KeyError, IndexError):
             text = str(value)
         
         self.display_manager.draw_text(text, x, y, color)