docs: add full NekoBox UI as a non-building reference

- Copy NekoBox's complete UI into reference/nekobox-ui/: all res (49 layouts,
  drawables, menus, values, fonts, raw) plus the ui/, widget/ and com.neko
  source packages.
- Lives outside app/src, so it is never compiled or packaged and does not
  affect the app or the build; a README explains why screens are ported one at
  a time rather than pasted wholesale.

Author: HSSkyBoy

reference/nekobox-ui/README.md

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+# NekoBox UI reference
+
+A verbatim copy of the **NekoBox for Android** UI, kept here purely as a
+reference for porting screens into MikuBox. **Nothing in this folder is part of
+the Gradle build** — it lives outside `app/src`, so it is never compiled,
+linked, or packaged. It will not affect the app or the build.
+
+## Contents
+
+- `res/` — the complete NekoBox `app/src/main/res` (all 49 layouts, ~141
+  drawables, menus, `values` (themes/attrs/styles/colors/strings/dimens),
+  fonts, raw animations, etc.).
+- `java/ui/` — activities, fragments and bottom sheets
+  (`io.nekohasekai.sagernet.ui`).
+- `java/widget/` — custom views used by the layouts
+  (`io.nekohasekai.sagernet.widget`).
+- `java/neko/` — MikuRay/`com.neko` UI helpers (particles, shape image views,
+  marquee text, blur, etc.).
+
+## Why it can't just be dropped into the app
+
+NekoBox's UI is welded to its **sing-box** stack:
+
+- ~97 of its source files use the sing-box data model (`Room SagerDatabase`,
+  `DataStore`, `ProxyEntity`, `ProfileManager`); MikuBox has none of these — it
+  uses the Mihomo core with a simple `SharedPreferences`-backed profile store.
+- Its `res/values` (theme, `attrs`, `colors`, `strings`) collide by name with
+  MikuBox's own resources.
+- ~28 files call the sing-box/libbox native core directly.
+
+So screens are ported **one at a time**, re-skinned onto MikuBox's Mihomo-backed
+data layer and Material3 theme, rather than pasted wholesale. Use these files to
+copy layouts/drawables and match the visual design.
+
+Source: <https://github.com/MatsuriDayo/NekoBoxForAndroid> (GPL-3.0).

reference/nekobox-ui/java/neko/particlesdrawable/CanvasParticlesView.java

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+/*
+ * Copyright (C) 2017 Yaroslav Mytkalyk
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.neko.particlesdrawable;
+
+import android.graphics.Canvas;
+import android.graphics.ColorFilter;
+import android.graphics.Paint;
+
+import androidx.annotation.ColorInt;
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+/**
+ * {@link IParticlesView} that draws on {@link Canvas}
+ */
+final class CanvasParticlesView implements IParticlesView {
+
+    private final Paint mPaint = new Paint(Paint.ANTI_ALIAS_FLAG | Paint.DITHER_FLAG);
+
+    @Nullable
+    private Canvas mCanvas;
+
+    void setCanvas(@Nullable final Canvas canvas) {
+        mCanvas = canvas;
+    }
+
+    @NonNull
+    Paint getPaint() {
+        return mPaint;
+    }
+
+    void setColorFilter(final ColorFilter colorFilter) {
+        mPaint.setColorFilter(colorFilter);
+    }
+
+    @Override
+    public void drawLine(final float startX, final float startY, final float stopX,
+            final float stopY, final float strokeWidth, @ColorInt final int color) {
+        if (mCanvas == null) {
+            throw new IllegalStateException("Called in wrong state");
+        }
+        mPaint.setStrokeWidth(strokeWidth);
+        mPaint.setColor(color);
+        mCanvas.drawLine(startX, startY, stopX, stopY, mPaint);
+    }
+
+    @Override
+    public void fillCircle(final float cx, final float cy, final float radius,
+            @ColorInt final int color) {
+        if (mCanvas == null) {
+            throw new IllegalStateException("Called in wrong state");
+        }
+        mPaint.setColor(color);
+        mCanvas.drawCircle(cx, cy, radius, mPaint);
+    }
+}

reference/nekobox-ui/java/neko/particlesdrawable/Defaults.java

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+/*
+ * Copyright (C) 2017 Yaroslav Mytkalyk
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.neko.particlesdrawable;
+
+import android.content.res.Resources;
+import android.graphics.Color;
+import android.util.TypedValue;
+
+import androidx.annotation.ColorInt;
+
+/**
+ * Default values are here.
+ */
+final class Defaults {
+
+    private Defaults() {
+        throw new UnsupportedOperationException();
+    }
+
+    static final int DEFAULT_DOT_NUMBER = 60;
+    static final float DEFAULT_MAX_DOT_RADIUS = TypedValue.applyDimension(
+            TypedValue.COMPLEX_UNIT_DIP, 3f, Resources.getSystem().getDisplayMetrics());
+    static final float DEFAULT_MIN_DOT_RADIUS = TypedValue.applyDimension(
+            TypedValue.COMPLEX_UNIT_DIP, 1f, Resources.getSystem().getDisplayMetrics());
+    static final float DEFAULT_LINE_THICKNESS = TypedValue.applyDimension(
+            TypedValue.COMPLEX_UNIT_DIP, 1, Resources.getSystem().getDisplayMetrics());
+    @ColorInt
+    static final int DEFAULT_DOT_COLOR = Color.WHITE;
+    @ColorInt
+    static final int DEFAULT_LINE_COLOR = Color.WHITE;
+    static final float DEFAULT_LINE_DISTANCE = TypedValue.applyDimension(
+            TypedValue.COMPLEX_UNIT_DIP, 86, Resources.getSystem().getDisplayMetrics());
+    static final float DEFAULT_STEP_MULTIPLIER = 1f;
+    static final int DEFAULT_DELAY = 10;
+}

reference/nekobox-ui/java/neko/particlesdrawable/IParticlesView.java

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+/*
+ * Copyright (C) 2017 Yaroslav Mytkalyk
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.neko.particlesdrawable;
+
+import androidx.annotation.ColorInt;
+
+/**
+ * Particles View
+ */
+interface IParticlesView {
+
+    void drawLine(float startX, float startY, float stopX, float stopY, float strokeWidth,
+            @ColorInt int color);
+
+    void fillCircle(float cx, float cy, float radius, @ColorInt int color);
+}

reference/nekobox-ui/java/neko/particlesdrawable/Particle.java

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+/*
+ * Copyright (C) 2017 Yaroslav Mytkalyk
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.neko.particlesdrawable;
+
+/**
+ * Represents a Particle by holding x and y coordinates, travel direction and step multiplier
+ */
+final class Particle {
+
+    /**
+     * Direction cosine
+     */
+    float dCos;
+
+    /**
+     * Direction sine
+     */
+    float dSin;
+
+    /**
+     * Current X
+     */
+    float x;
+
+    /**
+     * Current Y
+     */
+    float y;
+
+    /**
+     * Step multiplier for this dot
+     */
+    float stepMultiplier;
+
+    /**
+     * Radius multiplier for this dot
+     */
+    float radius;
+}