feat(org-chart): implement expandable layout and multi-company navigation

Integrate P5-1B through P5-4 shared Core layout, collapse, zoom/pan/fit, company roots and keyboard accessibility. Include React/HTML examples, virtual 20/100/300 employee fixtures, focused checks and the additive data contract.

packages/org-chart/src/data/types.ts

@@ -6,6 +6,8 @@ export type RelationType = 'cooperation' | 'support';
 
 export interface Organization {
   id: ID;
+  /** Auto company identity. Descendants inherit it; legacy datasets may omit it. */
+  companyId?: ID;
   parentId: ID | null;
   name: string;
   type: OrganizationType;

packages/org-chart/src/data/validate.ts

@@ -65,7 +65,8 @@ export function validateOrgChartDataset(input: unknown): ValidationResult {
   };
   if (!object(input, '$', ['schemaVersion', 'organizations', 'employees', 'affiliations', 'relations', 'presentation', 'metadata'])) return { valid: false, issues };
   if (input.schemaVersion !== SCHEMA_VERSION) issue('SCHEMA_VERSION', '$.schemaVersion', 'Unsupported or missing schema version.');
-  collection(input.organizations, '$.organizations', ['id', 'parentId', 'name', 'type', 'leaderId', 'displayOrder'], (org, path) => {
+  collection(input.organizations, '$.organizations', ['id', 'companyId', 'parentId', 'name', 'type', 'leaderId', 'displayOrder'], (org, path) => {
+    if (org.companyId !== undefined) text(org.companyId, `${path}.companyId`);
     text(org.parentId, `${path}.parentId`, true); text(org.name, `${path}.name`); text(org.leaderId, `${path}.leaderId`, true);
     choice(org.type, `${path}.type`, organizationTypes, 'INVALID_TYPE');
     if (!Number.isSafeInteger(org.displayOrder) || (org.displayOrder as number) < 0) issue('REQUIRED_VALUE', `${path}.displayOrder`, 'Expected a non-negative safe integer.');