Why

The memories MCP read tool already supports line_offset, but it cannot return a bounded line range. That makes it awkward to page through large memory files or request a small slice without relying on token truncation.

What changed

• add an optional max_lines parameter to the memories MCP read tool schema and request parsing
• cap local backend reads to the requested number of lines before token truncation
• treat max_lines = 0 as an invalid request and surface it as invalid_params
• add backend tests for bounded reads and invalid line request validation

Testing

• added coverage in memories/mcp/src/local_tests.rs for max_lines reads and invalid max_lines / line_offset requests