feat(collect): support soft deletion of one task

app/db.py

@@ -161,6 +161,8 @@ class Task:
     generated_at: Optional[str]
     applied_at: Optional[str]
     updated_at: str
+    deleted_at: Optional[str]
+    deleted_reason: Optional[str]
 
 
 @dataclass(frozen=True)
@@ -261,6 +263,8 @@ CREATE TABLE IF NOT EXISTS tasks (
   generated_at    TEXT,
   applied_at      TEXT,
   updated_at      TEXT NOT NULL,
+  deleted_at      TEXT,
+  deleted_reason  TEXT,
   UNIQUE(batch_id, source_file_abs, source_sheet, source_row)
 );
 
@@ -495,6 +499,7 @@ def init_db(path=None, conn=None) -> None:
             _ensure_task_image_task_columns(database)
             _ensure_task_cover_reset_columns(database)
             _ensure_task_product_status_columns(database)
+            _ensure_task_delete_columns(database)
             _migrate_legacy_product_status_defaults(database)
             _ensure_image_studio_project_suite_columns(database)
             _ensure_image_studio_project_draft_columns(database)
@@ -537,6 +542,15 @@ def _ensure_task_product_status_columns(database):
         database.execute("ALTER TABLE tasks ADD COLUMN product_status_at TEXT")
 
 
+def _ensure_task_delete_columns(database):
+    columns = {row["name"] for row in database.execute("PRAGMA table_info(tasks)").fetchall()}
+    if "deleted_at" not in columns:
+        database.execute("ALTER TABLE tasks ADD COLUMN deleted_at TEXT")
+    if "deleted_reason" not in columns:
+        database.execute("ALTER TABLE tasks ADD COLUMN deleted_reason TEXT")
+    database.execute("CREATE INDEX IF NOT EXISTS idx_tasks_deleted_at ON tasks(deleted_at)")
+
+
 def _migrate_legacy_product_status_defaults(database):
     """Treat pre-status-feature active batches as historically on-shelf once."""
 
@@ -548,6 +562,7 @@ def _migrate_legacy_product_status_defaults(database):
             product_status_at = NULL,
             updated_at = ?
         WHERE (product_status IS NULL OR TRIM(product_status) = '')
+          AND deleted_at IS NULL
           AND batch_id IN (
               SELECT id
               FROM batches
@@ -880,6 +895,7 @@ def list_tasks(
             params.append(value)
     if not include_deleted:
         clauses.append("b.deleted_at IS NULL")
+        clauses.append("t.deleted_at IS NULL")
     sql = "SELECT t.* FROM tasks t JOIN batches b ON b.id = t.batch_id"
     if clauses:
         sql += " WHERE " + " AND ".join(clauses)
@@ -920,11 +936,44 @@ def delete_batch(batch_id, reason=None, path=None, conn=None) -> dict:
             "image_paths": image_paths,
         }
 
+
+def delete_task(task_id, reason=None, path=None, conn=None) -> dict:
+    """Soft delete one inactive task without touching its source files or images."""
+
+    task_id = int(task_id)
+    with _connection(conn, path) as database:
+        task = get_task(task_id, conn=database)
+        if task is None:
+            raise DbError(f"任务不存在或已删除: {task_id}")
+        if task.status == "running":
+            raise DbError("任务正在处理，不能删除")
+        now = _now()
+        with database:
+            cursor = database.execute(
+                """
+                UPDATE tasks
+                SET deleted_at = ?, deleted_reason = ?, updated_at = ?
+                WHERE id = ? AND deleted_at IS NULL AND status <> 'running'
+                """,
+                (now, str(reason or ""), now, task_id),
+            )
+        if cursor.rowcount != 1:
+            raise DbError("任务已删除或正在处理，不能删除")
+        return {
+            "task_id": task_id,
+            "batch_id": task.batch_id,
+            "item_id": task.item_id,
+            "committed": int(task.committed or 0),
+            "deleted_at": now,
+        }
+
+
 def get_task(task_id, path=None, conn=None, include_deleted=False):
     clauses = ["t.id = ?"]
     params = [int(task_id)]
     if not include_deleted:
         clauses.append("b.deleted_at IS NULL")
+        clauses.append("t.deleted_at IS NULL")
     sql = "SELECT t.* FROM tasks t JOIN batches b ON b.id = t.batch_id"
     sql += " WHERE " + " AND ".join(clauses)
     with _connection(conn, path) as database: