feat(projects): Filter by award category

src/app/queries/projects.ts

@@ -38,6 +38,7 @@ export function useProjects(
   yearId: string,
   kind?: 'project' | 'idea',
   group?: string,
+  category?: string,
   search?: string,
   cursor?: string,
 ) {
@@ -47,10 +48,11 @@ export function useProjects(
   });
   if (kind) query.set('kind', kind);
   if (group) query.set('group', group);
+  if (category) query.set('category', category);
   if (search) query.set('q', search);
   if (cursor) query.set('cursor', cursor);
   return useQuery({
-    queryKey: ['projects', yearId, kind, group, search, cursor ?? null],
+    queryKey: ['projects', yearId, kind, group, category, search, cursor ?? null],
     queryFn: () => apiRequest<ProjectsResponse>(`/projects?${query}`),
     placeholderData: keepPreviousData,
   });

src/app/routes/ProjectsPage.tsx

@@ -36,6 +36,7 @@ export function ProjectsPage({isAdmin = false}: {isAdmin?: boolean}) {
   const {yearId} = useParams<{yearId: string}>();
   const [kind, setKind] = useState<'project' | 'idea'>('project');
   const [group, setGroup] = useState('');
+  const [category, setCategory] = useState('');
   const [searchInput, setSearchInput] = useState('');
   const [search, setSearch] = useState('');
   const [cursor, setCursor] = useState<string | undefined>();
@@ -49,6 +50,7 @@ export function ProjectsPage({isAdmin = false}: {isAdmin?: boolean}) {
     yearId,
     kind,
     kind === 'project' ? group || undefined : undefined,
+    kind === 'project' ? category || undefined : undefined,
     search || undefined,
     cursor,
   );
@@ -226,6 +228,25 @@ export function ProjectsPage({isAdmin = false}: {isAdmin?: boolean}) {
                   </select>
                 </label>
               )}
+              {kind === 'project' && ballot.data && ballot.data.categories.length > 0 && (
+                <label>
+                  <span>Award category</span>
+                  <select
+                    value={category}
+                    onChange={(event) => {
+                      setCategory(event.target.value);
+                      resetPagination();
+                    }}
+                  >
+                    <option value="">All award categories</option>
+                    {ballot.data.categories.map((item) => (
+                      <option value={item.id} key={item.id}>
+                        {item.name}
+                      </option>
+                    ))}
+                  </select>
+                </label>
+              )}
               <div className="projectViewToggle" role="group" aria-label="Project view">
                 {(['grid', 'list'] as const).map((option) => (
                   <button

src/worker/repositories/projects.ts

@@ -170,6 +170,7 @@ export async function listProjects(
     yearId: string;
     kind?: 'project' | 'idea';
     groupId?: string;
+    categoryId?: string;
     search?: string;
     limit: number;
     offset: number;
@@ -186,6 +187,15 @@ export async function listProjects(
     conditions.push('p.group_id = ?');
     bindings.push(options.groupId);
   }
+  if (options.categoryId) {
+    conditions.push(
+      `EXISTS (
+        SELECT 1 FROM project_nominations pn
+        WHERE pn.project_id = p.id AND pn.award_category_id = ?
+      )`,
+    );
+    bindings.push(options.categoryId);
+  }
   let relevanceOrder = '';
   if (options.search) {
     const escapedSearch = escapeLikePattern(options.search);

src/worker/routes/projects.ts

@@ -37,6 +37,7 @@ projectsRoutes.get('/', async (c) => {
       yearId,
       kind,
       groupId: c.req.query('group'),
+      categoryId: c.req.query('category'),
       search,
       limit,
       offset,

test/app/routes.test.tsx

@@ -918,6 +918,33 @@ describe('clickable project routes', () => {
     );
   });
 
+  it('filters projects by eligible award category', async () => {
+    mockProjectsOverview({
+      categories: [
+        {id: 'delight', yearId: '2026', name: 'Delight'},
+        {id: 'impact', yearId: '2026', name: 'Impact'},
+      ],
+      projects: [projectFixture],
+    });
+
+    renderRoute(<ProjectsPage />, '/years/2026/projects', '/years/:yearId/projects');
+    await screen.findByRole('heading', {name: 'A small machine'});
+
+    await userEvent.selectOptions(
+      await screen.findByLabelText('Award category'),
+      'delight',
+    );
+
+    await waitFor(() =>
+      expect(fetchMock).toHaveBeenCalledWith(
+        expect.stringMatching(
+          /\/api\/projects\?(?=.*year=2026)(?=.*kind=project)(?=.*category=delight)/,
+        ),
+        undefined,
+      ),
+    );
+  });
+
   it('live-updates server search without replacing the current list', async () => {
     let resolveSearch!: (response: Response) => void;
     const pendingSearch = new Promise<Response>((resolve) => {

test/projects/projects.test.ts

@@ -404,6 +404,32 @@ describe('project and history APIs', () => {
     ]);
   });
 
+  it('filters projects by eligible award category', async () => {
+    const delight = await createProject(memberToken, {
+      name: 'Delightful project',
+      nominationCategoryIds: [categoryId],
+    });
+    await createProject(memberToken, {
+      name: 'Craft project',
+      nominationCategoryIds: [secondCategoryId],
+    });
+    const both = await createProject(memberToken, {
+      name: 'Both categories',
+      nominationCategoryIds: [categoryId, secondCategoryId],
+    });
+
+    const matches = await api(
+      `/projects?year=${yearId}&kind=project&category=${categoryId}`,
+      memberToken,
+    );
+
+    expect(matches.status).toBe(200);
+    expect(matches.body.projects.map((project: {id: string}) => project.id)).toEqual([
+      both.id,
+      delight.id,
+    ]);
+  });
+
   it('searches titles and descriptions before pagination with relevant results first', async () => {
     const exact = await createProject(memberToken, {
       name: 'Signal',