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/components/forms/invoice-form.tsx

@@ -1,7 +1,7 @@
 "use client";
 
 import * as React from "react";
-import { useState, useEffect, useRef } from "react";
+import { useState, useEffect } from "react";
 import { useRouter } from "next/navigation";
 import { Button } from "~/components/ui/button";
 import { Card, CardContent, CardHeader, CardTitle } from "~/components/ui/card";

src/components/forms/invoice/invoice-workspace.tsx

@@ -3,9 +3,7 @@
 import * as React from "react";
 import { cn } from "~/lib/utils";
 import { Button } from "~/components/ui/button";
-import { Card, CardContent } from "~/components/ui/card";
-import { ScrollArea } from "~/components/ui/scroll-area";
-import { List, Calendar as CalendarIcon, Plus } from "lucide-react";
+import { List, Calendar as CalendarIcon } from "lucide-react";
 import { InvoiceLineItems } from "../invoice-line-items";
 import { InvoiceCalendarView } from "../invoice-calendar-view";
 import type { InvoiceFormData } from "./types";
@@ -19,7 +17,7 @@ interface InvoiceWorkspaceProps {
     updateItem: (index: number, field: string, value: string | number | Date) => void;
     moveItemUp: (index: number) => void;
     moveItemDown: (index: number) => void;
-    reorderItems: (items: any[]) => void;
+    reorderItems: (items: InvoiceFormData['items']) => void;
     className?: string;
 }
 

src/components/layout/sidebar-provider.tsx

@@ -20,7 +20,7 @@ export function SidebarProvider({ children }: { children: React.ReactNode }) {
     React.useEffect(() => {
         const saved = localStorage.getItem("sidebar-collapsed");
         if (saved) {
-            setIsCollapsed(JSON.parse(saved));
+            setIsCollapsed(JSON.parse(saved) as boolean);
         }
     }, []);
 

src/components/providers/animation-preferences-provider.tsx

@@ -403,9 +403,9 @@ export function useAnimationPreferences(): AnimationPreferencesContextValue {
     return {
       prefersReducedMotion: false,
       animationSpeedMultiplier: 1,
-      updatePreferences: () => { },
-      setPrefersReducedMotion: () => { },
-      setAnimationSpeedMultiplier: () => { },
+      updatePreferences: () => { /* no-op fallback */ },
+      setPrefersReducedMotion: () => { /* no-op fallback */ },
+      setAnimationSpeedMultiplier: () => { /* no-op fallback */ },
       isUpdating: false,
       lastSyncedAt: null,
     };