feat: add conditional logic types (ConditionOperator, ConditionRule, FieldConditions)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/types.ts

@@ -17,6 +17,31 @@ export type FieldType =
   | 'color'
   | 'time';
 
+// ---------------------------------------------------------------------------
+// Conditional Logic
+// ---------------------------------------------------------------------------
+
+export type ConditionOperator =
+  | 'equals'
+  | 'not_equals'
+  | 'contains'
+  | 'not_contains'
+  | 'is_empty'
+  | 'is_not_empty'
+  | 'greater_than'
+  | 'less_than';
+
+export interface ConditionRule {
+  fieldId: string;
+  operator: ConditionOperator;
+  value?: unknown;
+}
+
+export interface FieldConditions {
+  logic: 'and' | 'or';
+  rules: ConditionRule[];
+}
+
 export interface FormField {
   id: string;
   label: string;
@@ -34,6 +59,8 @@ export interface FormField {
   max?: number;
   /** For slider: step increment. */
   step?: number;
+  /** Conditional visibility rules. If undefined, field is always visible. */
+  conditions?: FieldConditions;
 }
 
 // ---------------------------------------------------------------------------