fix(frontend): enforce lint locally and in CI, fix all pre-existing violations

## Pre-commit hook
- Add .husky/pre-commit at repo root: runs `cd frontend && npm run lint`
- Update prepare script in package.json to auto-configure git hooks path
  on npm install (git -C .. config core.hooksPath .husky)
- Add lint step to CI unit-tests job so it catches issues before tests run
- Add generated dirs to .prettierignore (paraglide_bak*, test-results, .auth)
- Add src/lib/paraglide_bak* to .gitignore so ESLint can ignore them

## ESLint fixes (all pre-existing)
- Disable svelte/no-navigation-without-resolve: false positive in SvelteKit
  (rule targets Svelte 5 standalone routing, not SvelteKit <a href>)
- Fix svelte/require-each-key: add (item.id)/(item) keys to all {#each} blocks
  across 10 files — improves Svelte reconciliation performance
- Fix svelte/prefer-writable-derived in PersonTypeahead: $state+$effect → $derived
- Fix svelte/prefer-svelte-reactivity: URLSearchParams → SvelteURLSearchParams,
  Map → SvelteMap (enables Svelte reactive tracking)
- Fix @typescript-eslint/no-unused-vars: remove dead imports/variables

## Prettier
- Run npm run format to bring all source files in line with .prettierrc

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

frontend/src/routes/documents/new/+page.server.ts

@@ -3,8 +3,17 @@ import { env } from '$env/dynamic/private';
 import { createApiClient } from '$lib/api.server';
 import { parseBackendError, getErrorMessage } from '$lib/errors';
 
-export async function load({ fetch, locals }: { fetch: typeof globalThis.fetch; locals: App.Locals }) {
-	const canWrite = locals.user?.groups?.some((g: { permissions: string[] }) => g.permissions.includes('WRITE_ALL')) ?? false;
+export async function load({
+	fetch,
+	locals
+}: {
+	fetch: typeof globalThis.fetch;
+	locals: App.Locals;
+}) {
+	const canWrite =
+		locals.user?.groups?.some((g: { permissions: string[] }) =>
+			g.permissions.includes('WRITE_ALL')
+		) ?? false;
 	if (!canWrite) throw error(403, 'Forbidden');
 
 	const api = createApiClient(fetch);