fix: audit log pagination + full-width table, board card button alignment, light sidebar dither

- Audit log: backend only returns a next cursor when the page is full, so the
  "Load more" button no longer needs two clicks (and hides at the last page).
  Table now spans the full screen width and long detail JSON wraps instead of
  overflowing.
- Bounty board: pin each card's action row to the bottom so "Request
  assignment" lines up across equal-height cards.
- Light theme: restore the Y2K dither texture on the sidebar nav panel.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

internal/http/admin.go

@@ -102,14 +102,20 @@ func (s *Server) handleAdminPatchSettings(w http.ResponseWriter, r *http.Request
 
 func (s *Server) handleAdminAuditLog(w http.ResponseWriter, r *http.Request) {
 	q := r.URL.Query()
+	limit := atoiDefault(q.Get("limit"), 50)
+	if limit <= 0 || limit > 200 {
+		limit = 50
+	}
 	entries, err := s.store.ListAudit(r.Context(), q.Get("actorId"), q.Get("entityId"),
-		q.Get("cursor"), atoiDefault(q.Get("limit"), 50))
+		q.Get("cursor"), limit)
 	if err != nil {
 		s.internalError(w, r, "list audit", err)
 		return
 	}
+	// Only advertise a next cursor when the page is full; otherwise this is the
+	// last page and a further fetch would return nothing (the "click twice" bug).
 	next := ""
-	if len(entries) > 0 {
+	if len(entries) == limit {
 		next = entries[len(entries)-1].ID
 	}
 	writeJSON(w, http.StatusOK, map[string]any{"entries": entries, "nextCursor": next})