feat: scaffold Tauri v2 + React + TS with all dependencies

- Tauri v2 with React 19 + TypeScript + Vite 7
- Tauri plugins: fs, dialog, shell (registered in lib.rs)
- Filesystem permissions scoped to $APPDATA/openpylon/**
- Tailwind CSS v4 via @tailwindcss/vite
- shadcn/ui initialized with 12 components
- All app dependencies: Zustand, zundo, dnd-kit, Framer Motion,
  Zod, ulid, date-fns, react-markdown, remark-gfm
- Path alias @/* configured in tsconfig + vite

src-tauri/capabilities/default.json

@@ -0,0 +1,44 @@
+{
+  "$schema": "../gen/schemas/desktop-schema.json",
+  "identifier": "default",
+  "description": "Default permissions for OpenPylon",
+  "windows": ["main"],
+  "permissions": [
+    "core:default",
+    "opener:default",
+    "dialog:default",
+    "shell:default",
+    {
+      "identifier": "fs:default",
+      "allow": [{ "path": "$APPDATA/openpylon/**" }]
+    },
+    {
+      "identifier": "fs:allow-exists",
+      "allow": [{ "path": "$APPDATA/openpylon/**" }]
+    },
+    {
+      "identifier": "fs:allow-read",
+      "allow": [{ "path": "$APPDATA/openpylon/**" }]
+    },
+    {
+      "identifier": "fs:allow-write",
+      "allow": [{ "path": "$APPDATA/openpylon/**" }]
+    },
+    {
+      "identifier": "fs:allow-mkdir",
+      "allow": [{ "path": "$APPDATA/openpylon/**" }]
+    },
+    {
+      "identifier": "fs:allow-remove",
+      "allow": [{ "path": "$APPDATA/openpylon/**" }]
+    },
+    {
+      "identifier": "fs:allow-copy-file",
+      "allow": [{ "path": "$APPDATA/openpylon/**" }]
+    },
+    {
+      "identifier": "fs:allow-read-dir",
+      "allow": [{ "path": "$APPDATA/openpylon/**" }]
+    }
+  ]
+}