feat：LLM 分析文件并生成结构化建议

app/datafiles/profile.py

@@ -62,6 +62,29 @@ def profile_table(
     return profile, preview
 
 
+def read_rows(
+    path: Path,
+    offset: int,
+    limit: int,
+    sort_by: str | None = None,
+    descending: bool = False,
+) -> list[list[Any]]:
+    """读一页数据，单元格截断规则与预览相同；sort_by 必须是已校验过的列名，空值排最后"""
+    order = (
+        f" ORDER BY {quote_identifier(sort_by)} {'DESC' if descending else 'ASC'} NULLS LAST"
+        if sort_by
+        else ""
+    )
+    connection = connect({"t": path})
+    try:
+        rows = connection.execute(
+            f"FROM t{order} LIMIT {int(limit)} OFFSET {int(offset)}"
+        ).fetchall()
+    finally:
+        connection.close()
+    return [[json_value(value, PREVIEW_CELL_CHARS) for value in row] for row in rows]
+
+
 def _profile_column(
     connection: duckdb.DuckDBPyConnection,
     column: DataColumn,