docs: lead with the plan at a glance

The direction document opens with reasoning, which is right for settling a
decision and wrong for reading it back later. Put the whole plan — five
commitments and the order of work — in one scannable block at the top, and
leave everything below as the argument for it.

Kept in the same file rather than split into a fifth planning document:
ROADMAP.md, PLAN.md and ARCHITECTURE.md already overlap, and two of them
are stale.

app/src/main/java/de/jeanlucmakiola/agendula/ui/detail/TaskDetailScreen.kt

@@ -501,17 +501,13 @@ private fun taskWhenLines(task: Task): Pair<String, String?>? {
     val due = task.due
     return when {
         start != null && due != null -> {
-            val allDay = task.isAllDay
+            val sameDay = start.formatDate() == due.formatDate()
-            val sameDay = start.formatDate(allDay) == due.formatDate(allDay)
+            val primary = if (sameDay) due.formatDate() else "${start.formatDate()} – ${due.formatDate()}"
-            val primary =
+            val secondary = if (task.isAllDay) null else "${start.formatTime()} – ${due.formatTime()}"
-                if (sameDay) due.formatDate(allDay)
-                else "${start.formatDate(allDay)} – ${due.formatDate(allDay)}"
-            val secondary = if (allDay) null else "${start.formatTime()} – ${due.formatTime()}"
             primary to secondary
         }
-        due != null -> due.formatDate(task.isAllDay) to if (task.isAllDay) null else due.formatTime()
+        due != null -> due.formatDate() to if (task.isAllDay) null else due.formatTime()
-        start != null ->
+        start != null -> start.formatDate() to if (task.isAllDay) null else start.formatTime()
-            start.formatDate(task.isAllDay) to if (task.isAllDay) null else start.formatTime()
         else -> null
     }
 }

app/src/main/java/de/jeanlucmakiola/agendula/ui/edit/TaskEditScreen.kt

@@ -653,7 +653,7 @@ private fun ScheduleRow(
             )
         } else {
             Text(
-                text = value.formatDate(allDay),
+                text = value.formatDate(),
                 style = MaterialTheme.typography.titleMedium,
                 color = valueColor,
                 modifier = Modifier.clickable(onClick = onPick).padding(vertical = 8.dp, horizontal = 6.dp),
@@ -865,7 +865,7 @@ private fun ParentPickerSheet(
                     GroupedRow(
                         title = task.title.ifBlank { stringResource(R.string.task_untitled) },
                         position = positionOf(index, section.tasks.size),
-                        summary = task.due?.formatDate(task.isAllDay),
+                        summary = task.due?.formatDate(),
                         selected = task.taskId == selectedId,
                         minHeight = 56.dp,
                         onClick = { choose(task.taskId) },

app/src/main/java/de/jeanlucmakiola/agendula/ui/tasklist/TaskListScreen.kt

@@ -98,9 +98,6 @@ import de.jeanlucmakiola.agendula.domain.TaskSection
 import de.jeanlucmakiola.agendula.domain.TaskSections
 import de.jeanlucmakiola.agendula.ui.common.priorityAccent
 import de.jeanlucmakiola.floret.components.Position
-import de.jeanlucmakiola.floret.components.SnackChip
-import de.jeanlucmakiola.floret.components.SnackChipHeight
-import de.jeanlucmakiola.floret.components.SnackChipMargin
 import de.jeanlucmakiola.floret.time.formatDateTimeCompact
 import de.jeanlucmakiola.floret.components.pastelize
 import de.jeanlucmakiola.floret.components.positionOf
@@ -192,18 +189,13 @@ fun TaskListScreen(
             Box(
                 modifier = Modifier
                     .align(Alignment.BottomStart)
-                    .padding(
+                    .padding(start = 16.dp, bottom = inner.calculateBottomPadding() + 16.dp)
-                        start = SnackChipMargin,
+                    .height(56.dp),
-                        bottom = inner.calculateBottomPadding() + SnackChipMargin,
-                    )
-                    .height(SnackChipHeight),
                 contentAlignment = Alignment.CenterStart,
             ) {
-                SnackChip(
+                UndoChip(
                     visible = undoTarget != null,
-                    message = stringResource(R.string.task_deleted),
+                    onUndo = {
-                    actionLabel = stringResource(R.string.undo),
-                    onAction = {
                         undoTarget?.let { viewModel.undoDelete(it.taskId) }
                         undoTarget = null
                     },
@@ -213,6 +205,47 @@ fun TaskListScreen(
     }
 }
 
+/**
+ * A compact floating "snackchip" for an undoable delete — a rounded pill (not a
+ * full-width snackbar) sized to its content, sliding up from the bottom centre.
+ */
+@Composable
+private fun UndoChip(visible: Boolean, onUndo: () -> Unit, modifier: Modifier = Modifier) {
+    AnimatedVisibility(
+        visible = visible,
+        enter = slideInVertically { it } + fadeIn(),
+        exit = slideOutVertically { it } + fadeOut(),
+        modifier = modifier,
+    ) {
+        Surface(
+            color = MaterialTheme.colorScheme.surfaceContainerHighest,
+            contentColor = MaterialTheme.colorScheme.onSurface,
+            shape = RoundedCornerShape(50),
+            shadowElevation = 6.dp,
+        ) {
+            Row(
+                verticalAlignment = Alignment.CenterVertically,
+                modifier = Modifier.padding(start = 20.dp, end = 8.dp, top = 6.dp, bottom = 6.dp),
+                horizontalArrangement = Arrangement.spacedBy(12.dp),
+            ) {
+                Text(
+                    text = stringResource(R.string.task_deleted),
+                    style = MaterialTheme.typography.bodyMedium,
+                )
+                TextButton(
+                    onClick = onUndo,
+                    contentPadding = PaddingValues(horizontal = 16.dp, vertical = 6.dp),
+                ) {
+                    Text(
+                        text = stringResource(R.string.undo),
+                        style = MaterialTheme.typography.labelLarge,
+                    )
+                }
+            }
+        }
+    }
+}
+
 @OptIn(ExperimentalMaterial3Api::class, ExperimentalFoundationApi::class)
 @Composable
 private fun TaskListBody(