Update Fizzy logo with official PNG from repository

Replace custom SVG with the official app-icon.png (512x512) from
the Fizzy repository. This ensures brand consistency and uses the
authentic Fizzy branding.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

templates/compose/fizzy.yaml

@@ -2,7 +2,7 @@
 # slogan: Kanban tracking tool for issues and ideas by 37signals
 # category: productivity
 # tags: kanban, project management, issues, rails, ruby, basecamp, 37signals
-# logo: svgs/fizzy.svg
+# logo: svgs/fizzy.png
 # port: 80
 
 services:

templates/service-templates-latest.json

@@ -1160,7 +1160,7 @@
             "37signals"
         ],
         "category": "productivity",
-        "logo": "svgs/fizzy.svg",
+        "logo": "svgs/fizzy.png",
         "minversion": "0.0.0",
         "port": "80"
     },

templates/service-templates.json

@@ -1160,7 +1160,7 @@
             "37signals"
         ],
         "category": "productivity",
-        "logo": "svgs/fizzy.svg",
+        "logo": "svgs/fizzy.png",
         "minversion": "0.0.0",
         "port": "80"
     },