refactor(ui): remove abandoned Material-Design component library + screens layer

~9,988 lines of header-only UI code that no compiled translation unit reached,
verified by transitive include-reachability from every .cpp plus a symbol sweep
(all 28 component classes — Snackbar, Ripple, NavDrawerSpec, TabBarSpec,
TransitionManager, … — had zero references in live code):

- src/ui/material/ component library: the material.h umbrella, components/*
  (app_bar, cards, chips, dialogs, inputs, lists, nav_drawer, progress, slider,
  snackbar, tabs, text_fields), and the animation system (elevation, motion,
  ripple, transitions, app_layout) — 19 headers. Kept the live helpers the app
  actually uses directly: color_theme, colors, type/typography, draw_helpers,
  layout, project_icons, and components/buttons (included by mining_tab).
- src/ui/screens/ layer: main_layout, home_screen, send_screen, etc. — the
  original screen stack and the only consumer of the dead component library.
  The live UI runs through ui/windows/ (34 .cpp) + ui/pages/.
- src/embedded/resources.h: a superseded dragonx::embedded::Resources duplicate;
  the app uses src/resources/embedded_resources.h.

None were in CMakeLists or included by live code, so the build is unaffected.
Both variants build; full test suite passes; source-hygiene check clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/embedded/resources.h

@@ -1,65 +0,0 @@
-// DragonX Wallet - ImGui Edition
-// Copyright 2024-2026 The Hush Developers
-// Released under the GPLv3
-
-// Embedded Resources Header
-// This provides access to resources embedded in the binary
-
-#pragma once
-#include <cstddef>
-#include <cstdint>
-#include <string>
-#include <unordered_map>
-
-namespace dragonx {
-namespace embedded {
-
-// Forward declarations for embedded data (generated at build time)
-struct EmbeddedResource {
-    const unsigned char* data;
-    size_t size;
-};
-
-// Resource registry
-class Resources {
-public:
-    static Resources& instance() {
-        static Resources inst;
-        return inst;
-    }
-    
-    // Get embedded resource by name
-    // Returns nullptr if not found
-    const EmbeddedResource* get(const std::string& name) const {
-        auto it = resources_.find(name);
-        if (it != resources_.end()) {
-            return &it->second;
-        }
-        return nullptr;
-    }
-    
-    // Check if resource exists
-    bool has(const std::string& name) const {
-        return resources_.find(name) != resources_.end();
-    }
-    
-    // Register a resource (called during static init)
-    void registerResource(const std::string& name, const unsigned char* data, size_t size) {
-        resources_[name] = {data, size};
-    }
-
-private:
-    Resources() = default;
-    std::unordered_map<std::string, EmbeddedResource> resources_;
-};
-
-// Helper macro for registering resources
-#define REGISTER_EMBEDDED_RESOURCE(name, data, size) \
-    static struct _EmbeddedResourceRegister_##name { \
-        _EmbeddedResourceRegister_##name() { \
-            dragonx::embedded::Resources::instance().registerResource(#name, data, size); \
-        } \
-    } _embedded_resource_register_##name
-
-} // namespace embedded
-} // namespace dragonx