feat(gamification): clear auto_completed on uncomplete

uncomplete_task now clears auto_completed alongside done / done_at on
both the target row and the cascaded-parent reopen. Keeps the flag
accurate so a later re-completion via a different path is counted
correctly by the Phase 8 daily-count query.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

crates/storage/src/database.rs

@@ -487,7 +487,7 @@ pub async fn uncomplete_task(pool: &SqlitePool, id: &str) -> Result<()> {
         .await
         .map_err(|e| KonError::StorageError(format!("Begin transaction failed: {e}")))?;
 
-    sqlx::query("UPDATE tasks SET done = 0, done_at = NULL WHERE id = ?")
+    sqlx::query("UPDATE tasks SET done = 0, done_at = NULL, auto_completed = 0 WHERE id = ?")
         .bind(id)
         .execute(&mut *tx)
         .await
@@ -507,7 +507,10 @@ pub async fn uncomplete_task(pool: &SqlitePool, id: &str) -> Result<()> {
             .flatten();
 
     if let Some(pid) = parent_id {
-        sqlx::query("UPDATE tasks SET done = 0, done_at = NULL WHERE id = ? AND done = 1")
+        sqlx::query(
+            "UPDATE tasks SET done = 0, done_at = NULL, auto_completed = 0 \
+             WHERE id = ? AND done = 1",
+        )
         .bind(&pid)
         .execute(&mut *tx)
         .await
@@ -2077,4 +2080,48 @@ mod tests {
         assert_eq!(s1_auto, 0, "subtask completion is manual");
         assert_eq!(s2_auto, 0, "subtask completion is manual");
     }
+
+    #[tokio::test]
+    async fn uncomplete_clears_auto_completed_on_parent() {
+        let pool = test_pool().await;
+
+        insert_task(
+            &pool,
+            "parent",
+            "Parent task",
+            "inbox",
+            None,
+            None,
+            None,
+            None,
+        )
+        .await
+        .unwrap();
+        insert_subtask(&pool, "s1", "Only step", "parent")
+            .await
+            .unwrap();
+
+        // Cascade closes the parent with auto_completed = 1.
+        complete_subtask_and_check_parent(&pool, "s1")
+            .await
+            .unwrap();
+
+        // Uncompleting the subtask reopens the parent (existing invariant)
+        // and must also clear auto_completed on the parent so a later
+        // manual re-completion is counted cleanly.
+        uncomplete_task(&pool, "s1").await.unwrap();
+
+        let parent_done: i64 = sqlx::query_scalar("SELECT done FROM tasks WHERE id = 'parent'")
+            .fetch_one(&pool)
+            .await
+            .unwrap();
+        let parent_auto: i64 =
+            sqlx::query_scalar("SELECT auto_completed FROM tasks WHERE id = 'parent'")
+                .fetch_one(&pool)
+                .await
+                .unwrap();
+
+        assert_eq!(parent_done, 0, "parent reopens when child is uncompleted");
+        assert_eq!(parent_auto, 0, "auto_completed must clear on reopen");
+    }
 }