Add feature batch 2, subscription/recurring sync, smooth charts, and app icon

- Implement subscriptions view with bidirectional recurring transaction sync
- Add cascade delete/pause/resume between subscriptions and recurring
- Fix foreign key constraints when deleting recurring transactions
- Add cross-view instant refresh via callback pattern
- Replace Bezier chart smoothing with Fritsch-Carlson monotone Hermite interpolation
- Smooth budget sparklines using shared monotone_subdivide function
- Add vertical spacing to budget rows
- Add app icon (receipt on GNOME blue) in all sizes for desktop, web, and AppImage
- Add calendar, credit cards, forecast, goals, insights, and wishlist views
- Add date picker, numpad, quick-add, category combo, and edit dialog components
- Add import/export for CSV, JSON, OFX, QIF formats
- Add NLP transaction parsing, OCR receipt scanning, expression evaluator
- Add notification support, Sankey chart, tray icon
- Add demo data seeder with full DB wipe
- Expand database schema with subscriptions, goals, credit cards, and more

outlay-gtk/Cargo.toml

@@ -7,7 +7,8 @@ edition.workspace = true
 outlay-core = { path = "../outlay-core" }
 gtk = { package = "gtk4", version = "0.11", features = ["v4_10"] }
 adw = { package = "libadwaita", version = "0.9", features = ["v1_8"] }
+cairo = { package = "cairo-rs", version = "0.22", features = ["png"] }
 chrono = "0.4"
 gdk = { package = "gdk4", version = "0.11" }
-plotters = { version = "0.3", default-features = false, features = ["bitmap_backend", "bitmap_encoder", "line_series", "area_series"] }
 tokio = { version = "1", features = ["rt-multi-thread", "macros"] }
+ksni = { version = "0.3", features = ["tokio"] }