Add an edit/delete manage screen to the Android app

A new Manage screen (reached from the Post screen) lists published posts with
thumbnails and lets you edit a post's caption, date and tags or delete it to the
server's trash, over the same /api/photos, /api/edit and /api/delete endpoints
the web /manage uses.

UploadClient gains listPhotos/editPost/deletePost/fetchThumbnail, parsing JSON
with the built-in org.json (no new dependency) and posting edits/deletes as
urlencoded forms. The app sends no Origin or Sec-Fetch-Site header, so it passes
the server's same-origin CSRF check as a non-browser client; Basic auth is
already attached on every request. UploadViewModel holds the manage state,
loads the list, fetches thumbnails in the background, and applies edits/deletes
optimistically.

android/app/src/main/java/ws/inflo/photogallery/MainActivity.kt

@@ -20,6 +20,7 @@ import androidx.compose.runtime.setValue
 import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.core.content.ContextCompat
 import androidx.core.net.toUri
+import ws.inflo.photogallery.ui.ManageScreen
 import ws.inflo.photogallery.ui.PhotoGalleryTheme
 import ws.inflo.photogallery.ui.PostScreen
 import ws.inflo.photogallery.ui.SettingsScreen
@@ -37,6 +38,7 @@ class MainActivity : ComponentActivity() {
             PhotoGalleryTheme {
                 // Land on settings until there is somewhere to post to.
                 var showSettings by rememberSaveable { mutableStateOf(!viewModel.isConfigured) }
+                var showManage by rememberSaveable { mutableStateOf(false) }
 
                 val picker = rememberLauncherForActivityResult(
                     ActivityResultContracts.PickMultipleVisualMedia(),
@@ -57,8 +59,8 @@ class MainActivity : ComponentActivity() {
                     }
                 }
 
-                if (showSettings) {
-                    SettingsScreen(
+                when {
+                    showSettings -> SettingsScreen(
                         state = viewModel.config,
                         onBaseUrlChange = viewModel::setBaseUrl,
                         onUsernameChange = viewModel::setUsername,
@@ -70,8 +72,17 @@ class MainActivity : ComponentActivity() {
                             null
                         },
                     )
-                } else {
-                    PostScreen(
+
+                    showManage -> ManageScreen(
+                        state = viewModel.manage,
+                        onBack = { showManage = false },
+                        onRefresh = viewModel::loadManage,
+                        onSave = viewModel::saveEdit,
+                        onDelete = viewModel::deletePost,
+                        onDismissNotice = viewModel::clearManageNotice,
+                    )
+
+                    else -> PostScreen(
                         state = viewModel.post,
                         onPickImages = {
                             picker.launch(
@@ -87,6 +98,10 @@ class MainActivity : ComponentActivity() {
                         onSubmit = viewModel::submit,
                         onReset = viewModel::clear,
                         onOpenSettings = { showSettings = true },
+                        onOpenManage = {
+                            viewModel.loadManage()
+                            showManage = true
+                        },
                         onOpenUrl = ::openUrl,
                     )
                 }