Initial commit: FoFreeXit Phase 1 (Viewer) + Phase 2 (Annotate)

PDF viewer (render/search/text-select/thumbnails/outline) and annotation
engine (Highlight/Underline/Strikeout/Square/FreeText/Note) over PDFium +
lopdf, with Unicode font embedding for Vietnamese text and undo/redo.

app/src-tauri/Cargo.toml

@@ -0,0 +1,27 @@
+[package]
+name = "fofreexit-app"
+version = "0.1.0"
+edition = "2021"
+description = "FoFreeXit desktop app (Tauri shell)"
+license = "Apache-2.0"
+
+# Detach from the main crates/* workspace (Tauri uses its own build profiles).
+[workspace]
+
+[build-dependencies]
+tauri-build = { version = "2", features = [] }
+
+[dependencies]
+tauri = { version = "2", features = [] }
+tauri-plugin-dialog = "2"
+serde = { version = "1", features = ["derive"] }
+serde_json = "1"
+base64 = "0.22"
+image = "0.25"
+pdfium-render = "0.8"
+ff-engine = { path = "../../crates/ff-engine" }
+
+[profile.release]
+opt-level = "s"
+lto = true
+strip = true