- Add last_consumed_position tracking to StreamingToolParser to prevent
re-detecting already-executed tool calls
- Add mark_tool_calls_consumed() method to mark tool calls as processed
- Add find_first_tool_call_start() for forward scanning of tool patterns
- Replace try_parse_json_tool_call_from_buffer() with
try_parse_all_json_tool_calls_from_buffer() to find ALL tool calls
- Update has_incomplete_tool_call() and has_unexecuted_tool_call() to
only check unconsumed portion of buffer
- Fix tool execution loop to not reset parser when unexecuted tools remain
- Simplify should_auto_continue logic (remove redundant condition)
- Add comprehensive tests for auto-continue condition logic
