feat: card repository and home three-column layout

app/src/main/java/top/yeij/hearth/card/CardRepository.kt

@@ -0,0 +1,64 @@
+package top.yeij.hearth.card
+
+import android.util.Log
+import com.google.gson.Gson
+import top.yeij.hearth.cache.CacheManager
+import top.yeij.hearth.webapp.HttpClient
+
+// 首页卡片条目：id 唯一标识，priority 数字小者排前，entry 为卡片渲染入口
+// Home card entry: id is the unique key, smaller priority comes first, entry is the render entry point
+data class Card(val id: String, val name: String, val priority: Int, val entry: String)
+
+// 卡片目录仓库：拉取成功缓存并解析，失败回退缓存，无目录/无缓存返回内置 time 卡
+// Card catalog repository: cache+parse on success, fall back to cache on failure,
+// return builtin time card when there is no catalog or no cache
+class CardRepository(
+    private val http: HttpClient,
+    private val cache: CacheManager,
+    private val catalogUrl: String,
+) {
+    private val gson = Gson()
+
+    fun fetchCatalog(): List<Card> {
+        val body = http.get(catalogUrl)
+        if (body != null) {
+            cache.save(KEY, body)
+            Log.d(TAG, "fetchCatalog: fetched ${body.length} bytes from network")
+            return parse(body)
+        }
+        val cached = cache.load(KEY)
+        if (cached != null) {
+            Log.d(TAG, "fetchCatalog: network failed, using cache")
+            return parse(cached)
+        }
+        Log.d(TAG, "fetchCatalog: no network and no cache, return builtin time card")
+        return builtin()
+    }
+
+    // 解析目录 JSON：{ "cards": [ {id,name,priority,entry} ] }，字段缺失/非法时跳过该项
+    // Parse catalog JSON; skip malformed or missing-field entries
+    private fun parse(body: String): List<Card> {
+        val root = gson.fromJson(body, Map::class.java)
+        val list = root["cards"] as? List<*> ?: return builtin()
+        val parsed = list.mapNotNull { m ->
+            val map = m as? Map<*, *> ?: return@mapNotNull null
+            val id = map["id"] as? String ?: return@mapNotNull null
+            val name = map["name"] as? String ?: return@mapNotNull null
+            val priority = (map["priority"] as? Number)?.toInt() ?: return@mapNotNull null
+            val entry = map["entry"] as? String ?: return@mapNotNull null
+            Card(id, name, priority, entry)
+        }
+        // 内置 time 卡始终保留（追加在目录卡之后）
+        // builtin time card is always kept (appended after catalog cards)
+        return parsed + builtin()
+    }
+
+    // 内置卡：大字时间卡 priority 0，无目录时兜底
+    // Builtin card: big time card at priority 0, fallback when no catalog
+    private fun builtin(): List<Card> = listOf(Card("time", "大字时间", 0, "cards/time-card.html"))
+
+    companion object {
+        private const val TAG = "HearthCard"
+        private const val KEY = "card-catalog"
+    }
+}

app/src/main/java/top/yeij/hearth/webview/JsBridge.kt

@@ -2,6 +2,8 @@ package top.yeij.hearth.webview
 
 import android.util.Log
 import top.yeij.hearth.app.AppRepository
+import top.yeij.hearth.card.Card
+import top.yeij.hearth.card.CardRepository
 import top.yeij.hearth.webapp.WebApp
 import top.yeij.hearth.webapp.WebAppRepository
 
@@ -12,6 +14,7 @@ class JsBridge(
     private val darkMode: Boolean,
     private val appRepository: AppRepository? = null,
     private val webAppRepository: WebAppRepository? = null,
+    private val cardRepository: CardRepository? = null,
 ) {
     private val gson = com.google.gson.Gson()
 
@@ -42,4 +45,14 @@ class JsBridge(
     // Return the H5 web app manifest JSON (empty array when no repository wired)
     @android.webkit.JavascriptInterface
     fun fetchWebApps(): String = gson.toJson(webAppRepository?.fetchManifest() ?: emptyList<WebApp>())
+
+    // 返回首页卡片目录 JSON（无仓库时返回空数组；有仓库时由 fetchCatalog 保证内置 time 卡）
+    // Return the home card catalog JSON (empty array when no repository wired;
+    // fetchCatalog guarantees the builtin time card when wired)
+    @android.webkit.JavascriptInterface
+    fun fetchCards(): String {
+        val cards = cardRepository?.fetchCatalog() ?: emptyList<Card>()
+        Log.d("HearthBridge", "fetchCards: ${cards.size} cards")
+        return gson.toJson(cards)
+    }
 }