Add brand set and gear administration

docs/DESIGN_SYSTEM.md

@@ -87,6 +87,15 @@ Use the spacing tokens for new components. Prefer `8px`, `12px`, and `20px` gaps
 - Editors use `dashboard-editor` and appear before the affected table.
 - Data collections use `dashboard-table`, `dashboard-row`, and `table-heading`.
 - Keep tables dense and horizontally scrollable rather than wrapping columns unpredictably.
+- Threshold-based set bonuses use compact `effect-band` groups. Each threshold is
+  displayed as a fixed piece-count marker followed by its mapped stat and value,
+  keeping progression readable in editors and table summaries.
+- Multi-value compatibility fields use a dense `selection-grid` of checkbox
+  rows with a visible selected-count summary. Keep the entire row clickable and
+  preserve native checkbox semantics for keyboard and assistive-technology use.
+- When compatibility is conditional on another field, show only valid choices,
+  clear stale selections when the controlling field changes, and state required
+  minimum selections in both the section label and validation feedback.
 
 ### Forms