The JSON filter only suppresses tool calls at line boundaries. When
"Memory checkpoint: " was printed without a trailing newline, the LLM
response `{"tool": "remember", ...}` appeared on the same line and
leaked through to the UI.
Fix:
- Add trailing newline to "Memory checkpoint:" message
- Reset JSON filter state before streaming the response
Added test: test_tool_call_not_at_line_start_passes_through
Documents the filter behavior and references the fix location.
7c59d1993c