feat: fix project status counts, add top pagination and sortable columns

- Status counts now show each project's latest round state only
  (no more inflated counts from projects passing multiple rounds)
- Add pagination controls at top of projects, members, and observer lists
- Add sortable column headers to admin projects table (title, category,
  program, assignments, status) and members table (name, role, status,
  last login)
- Backend: add sortBy/sortDir params to project.list and user.list

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

src/server/routers/project.ts

@@ -76,6 +76,8 @@ export const projectRouter = router({
         hasAssignments: z.boolean().optional(),
         page: z.number().int().min(1).default(1),
         perPage: z.number().int().min(1).max(200).default(20),
+        sortBy: z.enum(['title', 'category', 'program', 'assignments', 'status', 'createdAt']).optional(),
+        sortDir: z.enum(['asc', 'desc']).optional(),
       })
     )
     .query(async ({ ctx, input }) => {
@@ -83,10 +85,23 @@ export const projectRouter = router({
         programId, roundId, excludeInRoundId, status, statuses, unassignedOnly, search, tags,
         competitionCategory, oceanIssue, country,
         wantsMentorship, hasFiles, hasAssignments,
-        page, perPage,
+        page, perPage, sortBy, sortDir,
       } = input
       const skip = (page - 1) * perPage
 
+      const dir = sortDir ?? 'desc'
+      const orderBy: Prisma.ProjectOrderByWithRelationInput = (() => {
+        switch (sortBy) {
+          case 'title':       return { title: dir }
+          case 'category':    return { competitionCategory: dir }
+          case 'program':     return { program: { name: dir } }
+          case 'assignments': return { assignments: { _count: dir } }
+          case 'status':      return { status: dir }
+          case 'createdAt':
+          default:            return { createdAt: dir }
+        }
+      })()
+
       // Build where clause
       const where: Record<string, unknown> = {}
 
@@ -151,7 +166,7 @@ export const projectRouter = router({
           where,
           skip,
           take: perPage,
-          orderBy: { createdAt: 'desc' },
+          orderBy,
           include: {
             program: { select: { id: true, name: true, year: true } },
             _count: { select: { assignments: true, files: true } },