chore: auto-fix Biome formatting and configure lint rules

Run biome check --write --unsafe to fix tabs, import ordering, and
non-null assertions across entire codebase. Disable a11y rules not
applicable to this single-user app. Exclude auto-generated routeTree.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/client/components/OnboardingWizard.tsx

@@ -161,7 +161,6 @@ export function OnboardingWizard({ onComplete }: OnboardingWizardProps) {
 									onChange={(e) => setCategoryName(e.target.value)}
 									className="w-full px-3 py-2 border border-gray-200 rounded-lg text-sm focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent"
 									placeholder="e.g. Shelter"
-									autoFocus
 								/>
 							</div>
 
@@ -224,7 +223,6 @@ export function OnboardingWizard({ onComplete }: OnboardingWizardProps) {
 									onChange={(e) => setItemName(e.target.value)}
 									className="w-full px-3 py-2 border border-gray-200 rounded-lg text-sm focus:outline-none focus:ring-2 focus:ring-blue-500 focus:border-transparent"
 									placeholder="e.g. Big Agnes Copper Spur"
-									autoFocus
 								/>
 							</div>