internal/gui: Wails app with Classic React variant + theme toggle

- app.go: App struct with stub bindings (RunCheck/StartEngine/
  StopEngine/GetStatus/Version) — emits check:result, check:done,
  engine:status, stats:update events. Real backend lands in Phase 1.
- run.go: wails.Run() with frameless 480x640 fixed window, Classic
  dark bg matching theme.
- embed.go: //go:embed all:frontend/dist for the Vite build output.
- frontend/: Vite + React project derived from `wails init -t react`.
  Removed default template assets and wired Classic variant from
  docs/design/v2/.
  - components/Classic.jsx: variant 1 with custom title bar
    (drag region, sun/moon theme toggle, min/close hooked to
    Wails WindowMinimise/Quit).
  - components/shared.jsx: useDrover hook adapted to call Wails
    bindings and listen on backend events instead of mock SCENARIOS.
    Added IconSun + IconMoon for the title-bar toggle.
  - App.jsx: owns mode state, wraps setMode in
    document.startViewTransition so the title-bar toggle gives a
    circle-reveal sweep from the cursor.
  - style.css: clean reset (overflow hidden, no scrollbars, brand
    background) — replaces the wails-react-template defaults.
  - wailsjs/go/gui/App.js: hand-written bindings since our App
    struct lives in package gui rather than the standard top-level
    main; `wails generate module` would have written package main
    bindings here.
- build/: standard wails artifacts (icon, manifest); will be
  consumed by `wails build` once we wire it through CI.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/gui/build/README.md

@@ -0,0 +1,35 @@
+# Build Directory
+
+The build directory is used to house all the build files and assets for your application. 
+
+The structure is:
+
+* bin - Output directory
+* darwin - macOS specific files
+* windows - Windows specific files
+
+## Mac
+
+The `darwin` directory holds files specific to Mac builds.
+These may be customised and used as part of the build. To return these files to the default state, simply delete them
+and
+build with `wails build`.
+
+The directory contains the following files:
+
+- `Info.plist` - the main plist file used for Mac builds. It is used when building using `wails build`.
+- `Info.dev.plist` - same as the main plist file but used when building using `wails dev`.
+
+## Windows
+
+The `windows` directory contains the manifest and rc files used when building with `wails build`.
+These may be customised for your application. To return these files to the default state, simply delete them and
+build with `wails build`.
+
+- `icon.ico` - The icon used for the application. This is used when building using `wails build`. If you wish to
+  use a different icon, simply replace this file with your own. If it is missing, a new `icon.ico` file
+  will be created using the `appicon.png` file in the build directory.
+- `installer/*` - The files used to create the Windows installer. These are used when building using `wails build`.
+- `info.json` - Application details used for Windows builds. The data here will be used by the Windows installer,
+  as well as the application itself (right click the exe -> properties -> details)
+- `wails.exe.manifest` - The main application manifest file.