feat(tauri): register dialog + fs plugins and grant capabilities

Wires the native Save/Open and SVG/PNG export paths used by the frontend IO
layer. Adds tauri-plugin-dialog and tauri-plugin-fs, initializes them in the
builder, and grants open/save/read/write permissions in the default capability.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src-tauri/Cargo.toml

@@ -23,3 +23,5 @@ serde = { version = "1.0", features = ["derive"] }
 log = "0.4"
 tauri = { version = "2.11.3" }
 tauri-plugin-log = "2"
+tauri-plugin-dialog = "2"
+tauri-plugin-fs = "2"

src-tauri/capabilities/default.json

@@ -2,10 +2,15 @@
   "$schema": "../gen/schemas/desktop-schema.json",
   "identifier": "default",
   "description": "enables the default permissions",
-  "windows": [
+  "windows": ["main"],
-    "main"
-  ],
   "permissions": [
-    "core:default"
+    "core:default",
+    "dialog:default",
+    "dialog:allow-open",
+    "dialog:allow-save",
+    "fs:default",
+    "fs:allow-read-text-file",
+    "fs:allow-write-text-file",
+    "fs:allow-write-file"
   ]
 }

src-tauri/src/lib.rs

@@ -1,6 +1,8 @@
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
 pub fn run() {
   tauri::Builder::default()
+    .plugin(tauri_plugin_dialog::init())
+    .plugin(tauri_plugin_fs::init())
     .setup(|app| {
       if cfg!(debug_assertions) {
         app.handle().plugin(