feat: card repository and home three-column layout

app/src/test/java/top/yeij/hearth/webview/JsBridgeTest.kt

@@ -2,6 +2,10 @@ package top.yeij.hearth.webview
 
 import org.junit.Assert.assertTrue
 import org.junit.Test
+import top.yeij.hearth.card.CardRepository
+import top.yeij.hearth.cache.CacheManager
+import top.yeij.hearth.webapp.HttpClient
+import java.io.File
 
 class JsBridgeTest {
     @Test
@@ -11,4 +15,27 @@ class JsBridgeTest {
         assertTrue(json.contains("\"widthPx\":800"))
         assertTrue(json.contains("\"darkMode\":true"))
     }
+
+    @Test
+    fun fetchCards_withoutRepository_returnsEmptyArray() {
+        val bridge = JsBridge(deviceWidthPx = 800, deviceHeightPx = 480, density = 2.0f, darkMode = true)
+        assertTrue(bridge.fetchCards() == "[]")
+    }
+
+    @Test
+    fun fetchCards_withRepository_returnsBuiltinTimeCard() {
+        val dir = File(System.getProperty("java.io.tmpdir"), "jb-cards")
+        val repo = CardRepository(
+            object : HttpClient { override fun get(url: String): String? = null },
+            CacheManager(dir),
+            "http://fake",
+        )
+        val bridge = JsBridge(
+            deviceWidthPx = 800, deviceHeightPx = 480, density = 2.0f, darkMode = true,
+            cardRepository = repo,
+        )
+        val json = bridge.fetchCards()
+        assertTrue(json.contains("\"id\":\"time\""))
+        dir.deleteRecursively()
+    }
 }