Extract shared logic into helpers:
- _parse_period(): Period parsing with fallback
- _format_token_display(): Token formatting with +/-
- _format_token_class(): CSS class based on token sign
- _build_patterns_html(): Pattern section HTML
- _build_narrative_html(): Narrative bullets HTML
- _build_metrics_row_html(): Metrics row HTML
- _render_scorecard_panel(): Single panel renderer
- _render_empty_scorecard(): Empty state renderer
- _render_error_scorecard(): Error state renderer
- _render_single_panel_wrapper(): Single panel wrapper
- _render_all_panels_grid(): Grid layout for all panels
Before:
- agent_scorecard_panel(): 108 lines
- all_scorecard_panels(): 106 lines
After:
- agent_scorecard_panel(): 26 lines
- all_scorecard_panels(): 26 lines
All helpers have docstrings. All 49 tests pass.
Fixes#1127
