Add ISAC weapon data management

docs/DESIGN_SYSTEM.md

@@ -204,3 +204,38 @@ buttons for reversible identity changes and muted red controls for destructive
 or restrictive changes. Every control must expose pointer, hover,
 focus-visible, pressed, disabled, and inline pending-spinner states; adjacent
 navigation links use the same height, typography, and interaction motion.
+
+### Weapon definition editor
+
+Complex progression definitions use a stacked control-surface editor: identity
+and fixed values first, then parallel tier cards, mutually exclusive talent
+pools, fixed base bonuses, and the augmentation sequence. Tier cards retain
+identical row ordering so values can be compared horizontally on wide screens
+and stack without changing meaning on narrow screens. System-derived augment
+steps appear as read-only numbered cells; editable effects use the shared
+attribute/value row pattern. Exotic is a status layered onto a weapon family,
+never a replacement for the family classification. Fixed base bonuses remain
+visually separate from tactical augmentation effects. Exotic definitions add a
+dedicated exotic-only talent after the two standard talent pools; their sixth
+augmentation cell communicates that this talent advances to Tier II.
+
+Large relationship sets use the searchable assignment control instead of
+checkbox walls. It keeps assigned records visible as removable chips, filters
+available records by name, renders at most thirty results at once, and exposes
+counts for both assignments and matches. Mutually exclusive pools pass their
+assigned IDs to one another as exclusions so invalid combinations cannot be
+selected. Keyboard focus, pressed state, empty results, and overflow remain
+explicit.
+Where a relationship has a global slot invariant, filter each assignment
+control at the data boundary instead of presenting cross-slot choices. Weapon
+talents are classified once as Talent 1 / Top or Talent 2 / Bottom in the
+talent registry; weapon editors only curate subsets from the matching slot.
+
+### ISAC editor lifecycle
+
+Successful saves have a consistent outcome throughout data management:
+editing an existing record closes the editor and returns the user to the registry;
+creating a new record keeps the editor open with a fresh blank definition for
+rapid consecutive entry. Failed validation leaves the current editor and
+entered values intact. Use a unique action result token so reactive handling
+runs exactly once and does not create update loops.