refactor(cache): move LargeSoftCache to commons/jvmAndroid, fix ICacheProvider types

- Move LargeSoftCache from amethyst/model to commons/jvmAndroid/model/cache
  so both Android and Desktop share the same WeakReference cache implementation
- Change ICacheProvider return types from Any? to proper types (User?, Note?)
  since these model classes already live in commons
- Remove unnecessary casts in ThreadAssembler, ChatNewMessageState, SearchBarState
- Improve LargeSoftCache.cleanUp() to use single-pass iterator (zero allocation)
- Update Android imports in LocalCache, LargeSoftCacheAddressExt, and test

Per Vitor's feedback on PR #1905: BoundedLargeCache evicts arbitrarily.
LargeSoftCache uses WeakReferences so GC respects the reference graph.

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/model/ThreadAssembler.kt

@@ -52,7 +52,7 @@ class ThreadAssembler(
                 ?.getOrNull(1)
         if (markedAsRoot != null) {
             // Check to see if there is an error in the tag and the root has replies
-            val rootNote = cache.getNoteIfExists(markedAsRoot) as? Note
+            val rootNote = cache.getNoteIfExists(markedAsRoot)
             if (rootNote?.replyTo?.isEmpty() == true) {
                 return cache.checkGetOrCreateNote(markedAsRoot)
             }

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/model/cache/ICacheProvider.kt

@@ -57,7 +57,7 @@ interface ICacheProvider {
      * @param pubkey The user's public key in hex format
      * @return The User if exists in cache, null otherwise
      */
-    fun getUserIfExists(pubkey: HexKey): Any?
+    fun getUserIfExists(pubkey: HexKey): User?
 
     /**
      * Counts users matching a predicate.
@@ -75,7 +75,7 @@ interface ICacheProvider {
      * @param hexKey The note's ID in hex format
      * @return The Note if exists in cache, null otherwise
      */
-    fun getNoteIfExists(hexKey: HexKey): Any?
+    fun getNoteIfExists(hexKey: HexKey): Note?
 
     /**
      * Gets an existing Note or creates a new one if it doesn't exist.
@@ -123,7 +123,7 @@ interface ICacheProvider {
     fun findUsersStartingWith(
         prefix: String,
         limit: Int = 50,
-    ): List<Any> = emptyList()
+    ): List<User> = emptyList()
 
     /**
      * Gets or creates a User by public key hex.
@@ -132,7 +132,7 @@ interface ICacheProvider {
      * @param pubkey The user's public key in hex format
      * @return The User (existing or newly created)
      */
-    fun getOrCreateUser(pubkey: HexKey): Any?
+    fun getOrCreateUser(pubkey: HexKey): User?
 
     fun justConsumeMyOwnEvent(event: Event): Boolean
 }

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/viewmodels/ChatNewMessageState.kt

@@ -24,7 +24,6 @@ import androidx.compose.runtime.Stable
 import androidx.compose.ui.text.input.TextFieldValue
 import com.vitorpamplona.amethyst.commons.model.IAccount
 import com.vitorpamplona.amethyst.commons.model.Note
-import com.vitorpamplona.amethyst.commons.model.User
 import com.vitorpamplona.amethyst.commons.model.cache.ICacheProvider
 import com.vitorpamplona.quartz.nip01Core.tags.hashtags.hashtags
 import com.vitorpamplona.quartz.nip01Core.tags.references.references
@@ -95,7 +94,7 @@ class ChatNewMessageState(
         if (currentRoom != null) {
             _recipientsMissingDmRelays.value =
                 currentRoom.users.any { hexKey ->
-                    val user = cache.getOrCreateUser(hexKey) as? User
+                    val user = cache.getOrCreateUser(hexKey)
                     user?.dmInboxRelays().isNullOrEmpty()
                 }
         } else {
@@ -141,7 +140,7 @@ class ChatNewMessageState(
     ) {
         val pTags =
             room.users.mapNotNull { hexKey ->
-                (cache.getOrCreateUser(hexKey) as? User)?.toPTag()
+                cache.getOrCreateUser(hexKey)?.toPTag()
             }
 
         val replyHint = _replyTo.value?.toEventHint<BaseDMGroupEvent>()

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/viewmodels/SearchBarState.kt

@@ -88,8 +88,7 @@ class SearchBarState(
             .debounce(debounceMs)
             .onEach { query ->
                 if (query.length >= 2 && _bech32Results.value.isEmpty()) {
-                    @Suppress("UNCHECKED_CAST")
-                    _cachedUserResults.value = cache.findUsersStartingWith(query, 20) as List<User>
+                    _cachedUserResults.value = cache.findUsersStartingWith(query, 20)
                 } else {
                     _cachedUserResults.value = emptyList()
                 }