Replace icon.svg with fini-clock specific icon

[chicks-net]

Description

The current icon.svg is using a generic/template icon. We should replace it with something specific to the fini-clock project. Discovered by code review in #5 .

Requirements

• Design or find an icon that represents the fini-clock project
• Replace icon.svg in the root directory
• Ensure the icon works well at various sizes (Godot uses it for the application icon)
• Consider using clock/time-related imagery

Acceptance Criteria

• New icon.svg file is in place
• Icon is appropriate for the fini-clock project theme
• Icon displays correctly in Godot editor
• Icon works as application icon when exported