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/[id]/edit/+page.server.ts

@@ -3,49 +3,60 @@ import { env } from '$env/dynamic/private';
 import { createApiClient } from '$lib/api.server';
 import { parseBackendError, getErrorMessage } from '$lib/errors';
 
-export async function load({ params, fetch, locals }: { params: { id: string }; 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');
+export async function load({
+	params,
+	fetch,
+	locals
+}: {
+	params: { id: string };
+	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 { id } = params;
-    const api = createApiClient(fetch);
+	const { id } = params;
+	const api = createApiClient(fetch);
 
-    const [docResult, personsResult] = await Promise.all([
-        api.GET('/api/documents/{id}', { params: { path: { id } } }),
-        api.GET('/api/persons')
-    ]);
+	const [docResult, personsResult] = await Promise.all([
+		api.GET('/api/documents/{id}', { params: { path: { id } } }),
+		api.GET('/api/persons')
+	]);
 
-    if (!docResult.response.ok) {
-        const code = (docResult.error as unknown as { code?: string })?.code;
-        throw error(docResult.response.status, getErrorMessage(code));
-    }
-    if (!personsResult.response.ok) {
-        throw error(personsResult.response.status, getErrorMessage('INTERNAL_ERROR'));
-    }
+	if (!docResult.response.ok) {
+		const code = (docResult.error as unknown as { code?: string })?.code;
+		throw error(docResult.response.status, getErrorMessage(code));
+	}
+	if (!personsResult.response.ok) {
+		throw error(personsResult.response.status, getErrorMessage('INTERNAL_ERROR'));
+	}
 
-    return {
-        document: docResult.data!,
-        persons: personsResult.data
-    };
+	return {
+		document: docResult.data!,
+		persons: personsResult.data
+	};
 }
 
 export const actions = {
-    default: async ({ request, params, fetch }) => {
-        // Raw fetch is used here because FormData multipart bodies are passed through
-        // directly from the browser without transformation.
-        const baseUrl = env.API_INTERNAL_URL || 'http://localhost:8080';
-        const formData = await request.formData();
+	default: async ({ request, params, fetch }) => {
+		// Raw fetch is used here because FormData multipart bodies are passed through
+		// directly from the browser without transformation.
+		const baseUrl = env.API_INTERNAL_URL || 'http://localhost:8080';
+		const formData = await request.formData();
 
-        const res = await fetch(`${baseUrl}/api/documents/${params.id}`, {
-            method: 'PUT',
-            body: formData
-        });
+		const res = await fetch(`${baseUrl}/api/documents/${params.id}`, {
+			method: 'PUT',
+			body: formData
+		});
 
-        if (!res.ok) {
-            const backendError = await parseBackendError(res);
-            return fail(res.status, { error: getErrorMessage(backendError?.code) });
-        }
+		if (!res.ok) {
+			const backendError = await parseBackendError(res);
+			return fail(res.status, { error: getErrorMessage(backendError?.code) });
+		}
 
-        throw redirect(303, `/documents/${params.id}`);
-    }
+		throw redirect(303, `/documents/${params.id}`);
+	}
 };