refactor: create FontSystem via cce_ui::create_font_system_with_system_fonts

Use the shared cce_ui helper (system + bundled CCE fonts) instead of a bare
glyphon::FontSystem::new(). For the five apps that used FontSystem::new() this
additionally loads the bundled CCE fonts; the two hybrids drop their manual
load_fonts_dir call. Additive — no font source is lost.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

 src/main.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/main.rs b/src/main.rs
index ad7c37f..182c590 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1295,7 +1295,7 @@ impl Application for ClearEmailApp {
             height: 600,
             scale_factor: 1.0,
             text_items: Vec::new(),
-            font_system: FontSystem::new(),
+            font_system: cce_ui::create_font_system_with_system_fonts(),
             needs_rebuild: true,
             ui_context: UiContext::new(),
         }