fix: resolve majority of lint errors across codebase

- Remove unused imports from page.tsx, clients/page.tsx, invoices/page.tsx
- Remove unused imports from invoice-form.tsx, invoice-workspace.tsx
- Move CustomTooltip outside component in revenue-chart.tsx (fixes react-hooks/static-components)
- Fix type safety in umami.ts (any -> unknown)
- Fix type safety in sidebar-provider.tsx (add type assertion)
- Add no-op comments to empty fallback functions in animation-preferences-provider.tsx
- Fix type safety in invoice-workspace.tsx (any[] -> typed array)

Note: dashboard/page.tsx still has ~55 type safety warnings related to 'any' types
in stats/invoice data. These are pre-existing and would require significant refactoring
of the dashboard data flow to properly type. TypeScript compilation passes.

src/server/umami.ts

@@ -10,14 +10,14 @@ type UmamiPayload = {
         url: string;
         website: string;
         name: string;
-        data?: Record<string, any>;
+        data?: Record<string, unknown>;
     };
     type: "event";
 };
 
 export async function trackServerEvent(
     eventName: string,
-    eventData?: Record<string, any>,
+    eventData?: Record<string, unknown>,
 ) {
     if (!env.NEXT_PUBLIC_UMAMI_WEBSITE_ID || !env.NEXT_PUBLIC_UMAMI_SCRIPT_URL) {
         console.warn("Umami not configured, skipping server-side event tracking");