feat: slide images moved to slides/img/, direct path in TOML, slides_test binary

- Moved 16 slide PNGs from assets/ to slides/img/
- Replaced [icons] mapping section with direct paths in icon field
- Added slides_test standalone binary for testing slideshows
- Added default-run = "yali-rs" in Cargo.toml to fix cargo run ambiguity
- Fixed edit dialog auto-resize and text field wrapping in partition.rs
- Updated branding.rs to load external slides from slides/ directory
- Removed [slides] section from branding.toml files
- Revamped CopyFilesJob with find-based progress tracking (rsync --out-format)
- Fixed install progress bar visibility logic
- Tweaked auto-install CLI output with sub-progress and current file
- Switched language-icon.svg to white fills for dark theme
- Minor locale fixes

Cargo.toml

@@ -2,6 +2,7 @@
 name = "yali-rs"
 version = "4.0.0"
 edition = "2024"
+default-run = "yali-rs"
 
 [dependencies]
 eframe        = { version = "0.27", features = ["default", "wgpu"] }
@@ -18,5 +19,13 @@ async-trait   = "0.1"
 chrono        = "0.4"
 xkbcommon = "0.9"
 
+[[bin]]
+name = "yali-rs"
+path = "src/main.rs"
+
+[[bin]]
+name = "slides_test"
+path = "src/bin/slides_test.rs"
+
 [patch.crates-io]
 # Yerel mudur veya comar-api kütüphaneleri buraya eklenebilir