feat: add @Preview composables for picture feed UI components

Adds 6 preview functions covering:
- PictureCardCompose with title, without title, and multi-image
- PictureCardCaption with title, without title, and long content
- Uses ThemeComparisonColumn for light/dark theme comparison
- Uses mock PictureEvent JSON data consumed via LocalCache

https://claude.ai/code/session_01KtuzFmDZXk67tW8QxPqmMy

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/pictures/PictureCardCompose.kt

@@ -185,7 +185,7 @@ private fun PictureCardImage(
 }
 
 @Composable
-private fun PictureCardCaption(event: PictureEvent) {
+internal fun PictureCardCaption(event: PictureEvent) {
     val title = event.title()
     val content = event.content
 

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/pictures/PictureCardComposePreview.kt

@@ -0,0 +1,218 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.ui.screen.loggedIn.pictures
+
+import androidx.compose.foundation.layout.Column
+import androidx.compose.foundation.layout.Spacer
+import androidx.compose.foundation.layout.fillMaxWidth
+import androidx.compose.foundation.layout.height
+import androidx.compose.foundation.layout.padding
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.runtime.Composable
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
+import androidx.compose.ui.tooling.preview.Preview
+import androidx.compose.ui.unit.dp
+import com.vitorpamplona.amethyst.model.LocalCache
+import com.vitorpamplona.amethyst.ui.components.LoadNote
+import com.vitorpamplona.amethyst.ui.navigation.navs.EmptyNav
+import com.vitorpamplona.amethyst.ui.screen.loggedIn.mockAccountViewModel
+import com.vitorpamplona.amethyst.ui.theme.ThemeComparisonColumn
+import com.vitorpamplona.quartz.nip01Core.core.Event
+import com.vitorpamplona.quartz.nip68Picture.PictureEvent
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.runBlocking
+import kotlinx.coroutines.withContext
+
+private const val SAMPLE_PICTURE_EVENT_JSON =
+    "{\"id\":\"a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2\"," +
+        "\"pubkey\":\"460c25e682fda7832b52d1f22d3d22b3176d972f60dcdc3212ed8c92ef85065c\"," +
+        "\"created_at\":1708695717," +
+        "\"kind\":20," +
+        "\"tags\":[[\"title\",\"Sunset at the Beach\"]," +
+        "[\"imeta\",\"url https://image.nostr.build/sample-sunset.jpg\"," +
+        "\"m image/jpeg\",\"dim 1200x800\",\"alt A beautiful sunset over the ocean\"," +
+        "\"blurhash LKO2:N%2Tw=w]~RBVZRi};RPxuwH\"]]," +
+        "\"content\":\"Caught this amazing sunset while walking along the shore. The colors were absolutely breathtaking, painting the sky in shades of orange and purple.\"," +
+        "\"sig\":\"a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2\"}"
+
+private const val SAMPLE_PICTURE_EVENT_NO_TITLE_JSON =
+    "{\"id\":\"b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3\"," +
+        "\"pubkey\":\"460c25e682fda7832b52d1f22d3d22b3176d972f60dcdc3212ed8c92ef85065c\"," +
+        "\"created_at\":1708695000," +
+        "\"kind\":20," +
+        "\"tags\":[[\"imeta\",\"url https://image.nostr.build/sample-mountain.jpg\"," +
+        "\"m image/jpeg\",\"dim 1080x1080\",\"alt Mountain landscape\"]]," +
+        "\"content\":\"Mountain vibes today. Fresh air and clear skies.\"," +
+        "\"sig\":\"b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3\"}"
+
+private const val SAMPLE_MULTI_IMAGE_EVENT_JSON =
+    "{\"id\":\"c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4\"," +
+        "\"pubkey\":\"460c25e682fda7832b52d1f22d3d22b3176d972f60dcdc3212ed8c92ef85065c\"," +
+        "\"created_at\":1708694000," +
+        "\"kind\":20," +
+        "\"tags\":[[\"title\",\"Travel Photos\"]," +
+        "[\"imeta\",\"url https://image.nostr.build/sample-travel1.jpg\"," +
+        "\"m image/jpeg\",\"dim 800x600\",\"alt City street\"]," +
+        "[\"imeta\",\"url https://image.nostr.build/sample-travel2.jpg\"," +
+        "\"m image/jpeg\",\"dim 800x600\",\"alt Market square\"]]," +
+        "\"content\":\"Exploring the old town district. Every corner has a story to tell. The architecture here is incredible and the food is even better.\"," +
+        "\"sig\":\"c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4\"}"
+
+@Preview
+@Composable
+private fun PictureCardComposePreview() {
+    val event = Event.fromJson(SAMPLE_PICTURE_EVENT_JSON) as PictureEvent
+    val accountViewModel = mockAccountViewModel()
+    val nav = EmptyNav()
+
+    runBlocking {
+        withContext(Dispatchers.IO) {
+            LocalCache.justConsume(event, null, false)
+        }
+    }
+
+    LoadNote(
+        baseNoteHex = "a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2",
+        accountViewModel = accountViewModel,
+    ) { baseNote ->
+        ThemeComparisonColumn {
+            if (baseNote != null) {
+                PictureCardCompose(
+                    baseNote = baseNote,
+                    accountViewModel = accountViewModel,
+                    nav = nav,
+                )
+            }
+        }
+    }
+}
+
+@Preview
+@Composable
+private fun PictureCardComposeNoTitlePreview() {
+    val event = Event.fromJson(SAMPLE_PICTURE_EVENT_NO_TITLE_JSON) as PictureEvent
+    val accountViewModel = mockAccountViewModel()
+    val nav = EmptyNav()
+
+    runBlocking {
+        withContext(Dispatchers.IO) {
+            LocalCache.justConsume(event, null, false)
+        }
+    }
+
+    LoadNote(
+        baseNoteHex = "b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3",
+        accountViewModel = accountViewModel,
+    ) { baseNote ->
+        ThemeComparisonColumn {
+            if (baseNote != null) {
+                PictureCardCompose(
+                    baseNote = baseNote,
+                    accountViewModel = accountViewModel,
+                    nav = nav,
+                )
+            }
+        }
+    }
+}
+
+@Preview
+@Composable
+private fun PictureCardComposeMultiImagePreview() {
+    val event = Event.fromJson(SAMPLE_MULTI_IMAGE_EVENT_JSON) as PictureEvent
+    val accountViewModel = mockAccountViewModel()
+    val nav = EmptyNav()
+
+    runBlocking {
+        withContext(Dispatchers.IO) {
+            LocalCache.justConsume(event, null, false)
+        }
+    }
+
+    LoadNote(
+        baseNoteHex = "c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4e5f6a1b2c3d4",
+        accountViewModel = accountViewModel,
+    ) { baseNote ->
+        ThemeComparisonColumn {
+            if (baseNote != null) {
+                PictureCardCompose(
+                    baseNote = baseNote,
+                    accountViewModel = accountViewModel,
+                    nav = nav,
+                )
+            }
+        }
+    }
+}
+
+@Preview
+@Composable
+private fun PictureCardCaptionWithTitlePreview() {
+    val event = Event.fromJson(SAMPLE_PICTURE_EVENT_JSON) as PictureEvent
+
+    ThemeComparisonColumn {
+        PictureCardCaption(event)
+    }
+}
+
+@Preview
+@Composable
+private fun PictureCardCaptionNoTitlePreview() {
+    val event = Event.fromJson(SAMPLE_PICTURE_EVENT_NO_TITLE_JSON) as PictureEvent
+
+    ThemeComparisonColumn {
+        PictureCardCaption(event)
+    }
+}
+
+@Preview
+@Composable
+private fun PictureCardCaptionLongContentPreview() {
+    ThemeComparisonColumn {
+        Column(
+            modifier = Modifier.padding(horizontal = 12.dp, vertical = 4.dp),
+        ) {
+            Text(
+                text = "A Very Long Title That Should Be Truncated When It Exceeds The Available Width",
+                style = MaterialTheme.typography.titleSmall,
+                fontWeight = FontWeight.Bold,
+                maxLines = 1,
+                overflow = TextOverflow.Ellipsis,
+            )
+            Spacer(modifier = Modifier.height(2.dp))
+            Text(
+                text =
+                    "This is a long description that spans multiple lines to test the three-line " +
+                        "truncation behavior. The text should be cut off after three lines with an " +
+                        "ellipsis. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed do " +
+                        "eiusmod tempor incididunt ut labore et dolore magna aliqua.",
+                style = MaterialTheme.typography.bodyMedium,
+                maxLines = 3,
+                overflow = TextOverflow.Ellipsis,
+                color = MaterialTheme.colorScheme.onSurfaceVariant,
+                modifier = Modifier.fillMaxWidth(),
+            )
+        }
+    }
+}