feat(user): context-aware default dashboard (§D.1)

user.getDefaultDashboard returns the highest-priority role for which the
user has actionable work right now — pending eval in active round, active
mentoring assignment, applicant project in active round, etc. — falling
back to static priority order if nothing is actionable.

src/app/page.tsx now reads roles[] (multi-role array) instead of just the
primary role, fixing the bug where mentor+juror users always landed on
their primary role's dashboard. Uses static priority for simplicity in
the server component; the context-aware procedure remains available for
client surfaces.

Tests cover six cases: super-admin, juror with active eval, juror+observer
fallback, mentor+juror in mentoring round, both-active-priority-tiebreak,
observer-only.

Plan: docs/superpowers/plans/2026-04-28-pr6-multi-role-and-workspace-previews.md

src/server/routers/user.ts

@@ -2039,4 +2039,109 @@ export const userRouter = router({
 
       return { ended: true }
     }),
+
+  /**
+   * Context-aware default dashboard. Returns the highest-priority role for
+   * which the user has actionable work right now, or the highest-priority
+   * role they hold (static fallback) if nothing is actionable.
+   *
+   * Priority order: SUPER_ADMIN > PROGRAM_ADMIN > AWARD_MASTER > JURY_MEMBER >
+   * MENTOR > APPLICANT > OBSERVER > AUDIENCE.
+   *
+   * Used by src/app/page.tsx to route users at login.
+   */
+  getDefaultDashboard: protectedProcedure.query(async ({ ctx }) => {
+    const user = await ctx.prisma.user.findUniqueOrThrow({
+      where: { id: ctx.user.id },
+      select: { id: true, roles: true, role: true },
+    })
+
+    const userRoles = new Set<UserRole>([...(user.roles ?? []), user.role])
+
+    type Entry = { role: UserRole; path: string; predicate: () => Promise<boolean> | boolean }
+    const PRIORITY: Entry[] = [
+      { role: 'SUPER_ADMIN', path: '/admin', predicate: () => true },
+      { role: 'PROGRAM_ADMIN', path: '/admin', predicate: () => true },
+      {
+        role: 'AWARD_MASTER',
+        path: '/award-master',
+        predicate: async () => {
+          const cnt = await ctx.prisma.awardJuror.count({ where: { userId: user.id } })
+          return cnt > 0
+        },
+      },
+      {
+        role: 'JURY_MEMBER',
+        path: '/jury',
+        predicate: async () => {
+          const cnt = await ctx.prisma.assignment.count({
+            where: {
+              userId: user.id,
+              isCompleted: false,
+              round: { status: 'ROUND_ACTIVE' },
+            },
+          })
+          return cnt > 0
+        },
+      },
+      {
+        role: 'MENTOR',
+        path: '/mentor',
+        predicate: async () => {
+          const cnt = await ctx.prisma.mentorAssignment.count({
+            where: {
+              mentorId: user.id,
+              workspaceEnabled: true,
+              project: {
+                projectRoundStates: {
+                  some: { round: { status: 'ROUND_ACTIVE' } },
+                },
+              },
+            },
+          })
+          return cnt > 0
+        },
+      },
+      {
+        role: 'APPLICANT',
+        path: '/applicant',
+        predicate: async () => {
+          const cnt = await ctx.prisma.teamMember.count({
+            where: {
+              userId: user.id,
+              project: {
+                projectRoundStates: {
+                  some: {
+                    round: { status: 'ROUND_ACTIVE' },
+                    state: { in: ['PENDING', 'IN_PROGRESS'] },
+                  },
+                },
+              },
+            },
+          })
+          return cnt > 0
+        },
+      },
+      { role: 'OBSERVER', path: '/observer', predicate: () => false },
+      { role: 'AUDIENCE', path: '/applicant', predicate: () => false },
+    ]
+
+    // Walk priority. Return first role the user holds whose predicate is true.
+    for (const entry of PRIORITY) {
+      if (!userRoles.has(entry.role)) continue
+      const has = await entry.predicate()
+      if (has) {
+        return { role: entry.role, path: entry.path, reason: 'has-active-work' as const }
+      }
+    }
+
+    // Static fallback: highest-priority role they hold.
+    for (const entry of PRIORITY) {
+      if (userRoles.has(entry.role)) {
+        return { role: entry.role, path: entry.path, reason: 'static-fallback' as const }
+      }
+    }
+
+    return { role: 'APPLICANT' as UserRole, path: '/applicant', reason: 'static-fallback' as const }
+  }),
 })