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/hooks.server.ts

@@ -11,7 +11,12 @@ const handleLocaleDetection: Handle = ({ event, resolve }) => {
 	if (!event.cookies.get(cookieName)) {
 		const locale = detectLocale(event.request.headers.get('accept-language') ?? '');
 		if (locale) {
-			event.cookies.set(cookieName, locale, { path: '/', sameSite: 'lax', maxAge: cookieMaxAge, httpOnly: false });
+			event.cookies.set(cookieName, locale, {
+				path: '/',
+				sameSite: 'lax',
+				maxAge: cookieMaxAge,
+				httpOnly: false
+			});
 		}
 	}
 	return resolve(event);
@@ -25,65 +30,63 @@ const handleAuth: Handle = async ({ event, resolve }) => {
 	return resolve(event);
 };
 
-const handleParaglide: Handle = ({ event, resolve }) => paraglideMiddleware(event.request, ({ request, locale }) => {
-	event.request = request;
+const handleParaglide: Handle = ({ event, resolve }) =>
+	paraglideMiddleware(event.request, ({ request, locale }) => {
+		event.request = request;
 
-	return resolve(event, {
-		transformPageChunk: ({ html }) => html.replace('%paraglide.lang%', locale)
+		return resolve(event, {
+			transformPageChunk: ({ html }) => html.replace('%paraglide.lang%', locale)
+		});
 	});
-});
-
 
 const userGroup: Handle = async ({ event, resolve }) => {
-	 const auth = event.cookies.get('auth_token');
+	const auth = event.cookies.get('auth_token');
 
-    if (auth) {
-        try {
-            const apiUrl = env.API_INTERNAL_URL || 'http://localhost:8080';
-            const response = await fetch(`${apiUrl}/api/users/me`, {
-                        headers: { Authorization: auth }
+	if (auth) {
+		try {
+			const apiUrl = env.API_INTERNAL_URL || 'http://localhost:8080';
+			const response = await fetch(`${apiUrl}/api/users/me`, {
+				headers: { Authorization: auth }
+			});
+			if (response.ok) {
+				const user = await response.json();
+				event.locals.user = user;
+			}
+		} catch (error) {
+			console.error('Error fetching user in hook:', error);
+		}
+	}
 
-            });
-            if (response.ok) {
-                const user = await response.json();
-                event.locals.user = user;
-            }
-        } catch (error) {
-            console.error('Error fetching user in hook:', error);
-        }
-    }
-
-    return resolve(event);
+	return resolve(event);
 };
 
-
 export const handleFetch: HandleFetch = async ({ event, request, fetch }) => {
-    const apiUrl = env.API_INTERNAL_URL || 'http://localhost:8080';
-    const isApi = request.url.startsWith(apiUrl) || request.url.includes('/api/');
-    const isNotLoginTest = !request.url.includes('/api/users/me');
+	const apiUrl = env.API_INTERNAL_URL || 'http://localhost:8080';
+	const isApi = request.url.startsWith(apiUrl) || request.url.includes('/api/');
+	const isNotLoginTest = !request.url.includes('/api/users/me');
 
-    if (isApi && isNotLoginTest) {
-        const token = event.cookies.get('auth_token');
+	if (isApi && isNotLoginTest) {
+		const token = event.cookies.get('auth_token');
 
-        if (!token) {
-            return new Response('Unauthorized', { status: 401 });
-        }
+		if (!token) {
+			return new Response('Unauthorized', { status: 401 });
+		}
 
-        // Clone the request first to preserve the body
-        const clonedRequest = request.clone();
+		// Clone the request first to preserve the body
+		const clonedRequest = request.clone();
 
-        // Create new request with Authorization header and preserved body
-        const modifiedRequest = new Request(clonedRequest, {
-            headers: {
-                ...Object.fromEntries(clonedRequest.headers),
-                'Authorization': token
-            }
-        });
+		// Create new request with Authorization header and preserved body
+		const modifiedRequest = new Request(clonedRequest, {
+			headers: {
+				...Object.fromEntries(clonedRequest.headers),
+				Authorization: token
+			}
+		});
 
-        return fetch(modifiedRequest);
-    }
+		return fetch(modifiedRequest);
+	}
 
-    return fetch(request);
+	return fetch(request);
 };
 
 export const handle = sequence(userGroup, handleAuth, handleLocaleDetection, handleParaglide);