perf: 限制 WebP 动画重复次数并简化入场动画，减少帧丢失

Perfetto trace 分析显示 75.6% 帧延迟，根因为 250x250 WebP
持续以 11-14 FPS 无限循环解码。每次解码周期导致 4-26 帧延迟。

- AnimatedGif: repeatCount(2) 限制动画播放 3 次后停止
- AnimatedGif: 移除两阶段弹跳动画，改为 150ms 淡入
- README: 添加构建命令和产物路径

README.md

@@ -19,4 +19,30 @@
 - 双模块:`:shared`(UI + 逻辑) · `:androidApp`(薄壳)
 - iOS 入口为 `MainViewController.kt`,Xcode 工程位于 `iosApp/`
 
+## 构建
+
+```bash
+# Debug
+./gradlew :app:assembleDebug          # 构建 debug APK
+./gradlew :app:installDebug           # 安装 debug APK 到设备
+
+# Release
+./gradlew :app:assembleRelease        # 构建 release APK
+./gradlew :app:installBenchmark       # 安装 benchmark（release + 可调试）APK
+
+# 测试
+./gradlew :core:testDebugUnitTest                          # 运行全部测试
+./gradlew :core:testDebugUnitTest --tests "plus.rua.project.ui.CalendarUtilsTest"  # 运行单个测试
+
+# Baseline Profile（需要连接设备）
+./gradlew :macrobenchmark:updateBaselineProfile                       # 一键生成 + 自动复制到 :core
+./gradlew :macrobenchmark:connectedBenchmarkAndroidTest               # 仅运行基准测试
+
+# 性能 Profiling（需要连接设备）
+./scripts/profile.sh                  # 默认 8 秒
+./scripts/profile.sh 15               # 自定义时长
+```
+
+构建产物位于 `app/build/outputs/apk/<variant>/` 目录。
+
 线条小狗表情包来自 https://www.douban.com/group/topic/264788645/?_i=9181692phrDzjR,9241256phrDzjR

core/src/main/kotlin/plus/rua/project/ui/AnimatedGif.kt

@@ -2,8 +2,6 @@ package plus.rua.project.ui
 
 import androidx.compose.animation.core.Animatable
 import androidx.compose.animation.core.FastOutSlowInEasing
-import androidx.compose.animation.core.Spring
-import androidx.compose.animation.core.spring
 import androidx.compose.animation.core.tween
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
@@ -11,6 +9,9 @@ import androidx.compose.runtime.remember
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.graphicsLayer
 import com.github.panpf.sketch.AsyncImage
+import com.github.panpf.sketch.rememberAsyncImageState
+import com.github.panpf.sketch.request.ImageOptions
+import com.github.panpf.sketch.request.repeatCount
 import plus.rua.project.getWebpUri
 
 /**
@@ -18,12 +19,16 @@ import plus.rua.project.getWebpUri
  */
 private val WEBP_FILES = (1..152).map { "${it.toString().padStart(3, '0')}.webp" }
 
+private const val REPEAT_COUNT = 2
+
 /**
- * 显示动画 GIF 图片，切换日期时随机选择一个。
+ * 显示动画 WebP 图片，切换日期时随机选择一个。
+ *
+ * 动画播放 3 次（1 + [REPEAT_COUNT]）后停止，避免持续解码导致的帧丢失。
  *
  * @param modifier 应用于图片的 Modifier
  * @param contentDescription 无障碍描述
- * @param seed 用于控制重新随机时机的 key，变化时重新选择 GIF
+ * @param seed 用于控制重新随机时机的 key，变化时重新选择 WebP
  */
 @Composable
 fun AnimatedGif(
@@ -33,28 +38,26 @@ fun AnimatedGif(
 ) {
     val webpFile = remember(seed) { WEBP_FILES.random() }
     val uri = remember(webpFile) { getWebpUri(webpFile) }
-    val scale = remember { Animatable(0f) }
+    val alpha = remember { Animatable(0f) }
 
     LaunchedEffect(seed) {
-        scale.snapTo(0f)
-        scale.animateTo(
-            targetValue = 1.1f,
-            animationSpec = tween(250, easing = FastOutSlowInEasing),
-        )
-        scale.animateTo(
+        alpha.snapTo(0f)
+        alpha.animateTo(
             targetValue = 1f,
-            animationSpec = spring(dampingRatio = Spring.DampingRatioMediumBouncy),
+            animationSpec = tween(150, easing = FastOutSlowInEasing),
         )
     }
 
+    val state = rememberAsyncImageState(
+        options = remember { ImageOptions { repeatCount(REPEAT_COUNT) } }
+    )
+
     AsyncImage(
         uri = uri,
         contentDescription = contentDescription,
-        modifier = modifier
-            .graphicsLayer {
-                scaleX = scale.value
-                scaleY = scale.value
-                alpha = scale.value.coerceIn(0f, 1f)
-            },
+        state = state,
+        modifier = modifier.graphicsLayer {
+            this.alpha = alpha.value
+        },
     )
 }