Add page long-press menu (delete/export JPG) in view all pages

- Long-press a page thumbnail to show context menu with Delete and
  Export as JPG options
- Delete shows confirmation dialog
- Export renders page at 300 DPI and shares via intent
- FAB always creates new pages (no empty-page restriction in page list)
- Note: drag-to-reorder deferred — requires custom grid drag handling

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

app/src/main/kotlin/net/metacircular/engpad/ui/pages/PageListScreen.kt

@@ -1,11 +1,12 @@
 package net.metacircular.engpad.ui.pages
 
-import android.graphics.Color as AndroidColor
 import android.graphics.Paint as AndroidPaint
 import android.graphics.Path as AndroidPath
 import androidx.compose.foundation.Canvas
-import androidx.compose.foundation.clickable
+import androidx.compose.foundation.ExperimentalFoundationApi
+import androidx.compose.foundation.combinedClickable
 import androidx.compose.foundation.layout.Arrangement
+import androidx.compose.foundation.layout.Box
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.aspectRatio
 import androidx.compose.foundation.layout.fillMaxSize
@@ -14,12 +15,16 @@ import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.grid.GridCells
 import androidx.compose.foundation.lazy.grid.LazyVerticalGrid
 import androidx.compose.foundation.lazy.grid.items
+import androidx.compose.material3.AlertDialog
 import androidx.compose.material3.Card
+import androidx.compose.material3.DropdownMenu
+import androidx.compose.material3.DropdownMenuItem
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.FloatingActionButton
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Scaffold
 import androidx.compose.material3.Text
+import androidx.compose.material3.TextButton
 import androidx.compose.material3.TopAppBar
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.LaunchedEffect
@@ -27,20 +32,24 @@ import androidx.compose.runtime.collectAsState
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.remember
+import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.runtime.setValue
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.graphics.drawscope.drawIntoCanvas
 import androidx.compose.ui.graphics.nativeCanvas
-import androidx.core.graphics.withScale
+import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.unit.dp
+import androidx.core.graphics.withScale
 import androidx.lifecycle.viewmodel.compose.viewModel
+import kotlinx.coroutines.launch
 import net.metacircular.engpad.data.db.EngPadDatabase
 import net.metacircular.engpad.data.db.toFloatArray
 import net.metacircular.engpad.data.model.Page
 import net.metacircular.engpad.data.model.PageSize
 import net.metacircular.engpad.data.model.Stroke
 import net.metacircular.engpad.data.repository.PageRepository
+import net.metacircular.engpad.ui.export.PdfExporter
 
 @OptIn(ExperimentalMaterial3Api::class)
 @Composable
@@ -59,6 +68,10 @@ fun PageListScreen(
     )
     val pages by viewModel.pages.collectAsState()
     val aspectRatio = pageSize.widthPt.toFloat() / pageSize.heightPt.toFloat()
+    val context = LocalContext.current
+    val scope = rememberCoroutineScope()
+
+    var pageToDelete by remember { mutableStateOf<Page?>(null) }
 
     Scaffold(
         topBar = {
@@ -97,13 +110,45 @@ fun PageListScreen(
                         aspectRatio = aspectRatio,
                         repository = repository,
                         onClick = { onPageClick(page.id, pageSize) },
+                        onDelete = { pageToDelete = page },
+                        onExportJpg = {
+                            scope.launch {
+                                val strokes = viewModel.getStrokes(page.id)
+                                val file = PdfExporter.exportPageAsJpg(
+                                    context = context,
+                                    notebookTitle = notebookTitle,
+                                    pageSize = pageSize,
+                                    pageNumber = page.pageNumber,
+                                    strokes = strokes,
+                                )
+                                PdfExporter.shareFile(context, file, "image/jpeg")
+                            }
+                        },
                     )
                 }
             }
         }
     }
+
+    pageToDelete?.let { page ->
+        AlertDialog(
+            onDismissRequest = { pageToDelete = null },
+            title = { Text("Delete Page") },
+            text = { Text("Delete page ${page.pageNumber}? This cannot be undone.") },
+            confirmButton = {
+                TextButton(onClick = {
+                    viewModel.deletePage(page.id)
+                    pageToDelete = null
+                }) { Text("Delete") }
+            },
+            dismissButton = {
+                TextButton(onClick = { pageToDelete = null }) { Text("Cancel") }
+            },
+        )
+    }
 }
 
+@OptIn(ExperimentalFoundationApi::class)
 @Composable
 private fun PageThumbnail(
     page: Page,
@@ -111,8 +156,11 @@ private fun PageThumbnail(
     aspectRatio: Float,
     repository: PageRepository,
     onClick: () -> Unit,
+    onDelete: () -> Unit,
+    onExportJpg: () -> Unit,
 ) {
     var strokes by remember(page.id) { mutableStateOf<List<Stroke>>(emptyList()) }
+    var showMenu by remember { mutableStateOf(false) }
 
     LaunchedEffect(page.id) {
         strokes = repository.getStrokes(page.id)
@@ -120,10 +168,15 @@ private fun PageThumbnail(
 
     Column(
         horizontalAlignment = Alignment.CenterHorizontally,
-        modifier = Modifier.clickable(onClick = onClick),
     ) {
+        Box {
             Card(
-            modifier = Modifier.fillMaxWidth(),
+                modifier = Modifier
+                    .fillMaxWidth()
+                    .combinedClickable(
+                        onClick = onClick,
+                        onLongClick = { showMenu = true },
+                    ),
             ) {
                 Canvas(
                     modifier = Modifier
@@ -161,6 +214,26 @@ private fun PageThumbnail(
                     }
                 }
             }
+            DropdownMenu(
+                expanded = showMenu,
+                onDismissRequest = { showMenu = false },
+            ) {
+                DropdownMenuItem(
+                    text = { Text("Export as JPG") },
+                    onClick = {
+                        showMenu = false
+                        onExportJpg()
+                    },
+                )
+                DropdownMenuItem(
+                    text = { Text("Delete page") },
+                    onClick = {
+                        showMenu = false
+                        onDelete()
+                    },
+                )
+            }
+        }
         Text(
             text = "Page ${page.pageNumber}",
             style = MaterialTheme.typography.bodySmall,

app/src/main/kotlin/net/metacircular/engpad/ui/pages/PageListViewModel.kt

@@ -8,6 +8,7 @@ import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
 import net.metacircular.engpad.data.model.Page
+import net.metacircular.engpad.data.model.Stroke
 import net.metacircular.engpad.data.repository.PageRepository
 
 class PageListViewModel(
@@ -24,6 +25,15 @@ class PageListViewModel(
         }
     }
 
+    fun deletePage(pageId: Long) {
+        viewModelScope.launch {
+            repository.deletePage(pageId)
+        }
+    }
+
+    suspend fun getStrokes(pageId: Long): List<Stroke> =
+        repository.getStrokes(pageId)
+
     class Factory(
         private val notebookId: Long,
         private val repository: PageRepository,