harness-base: pin hive-dashboard-links doc ref to section anchor (argus 🟡 on #823)

nix/templates/harness-base.nix

@@ -1244,7 +1244,8 @@ in
 
     # Write declared dashboardLinks to the state dir so hive-c0re can
     # read them without accessing the container's /etc/ from the host.
-    # Best-effort oneshot (always exit 0): docs/conventions.md.
+    # Best-effort oneshot (always exit 0):
+    # docs/conventions.md::Best-effort oneshot services.
     systemd.services.hive-dashboard-links = lib.mkIf (config.hyperhive.dashboardLinks != [ ]) {
       description = "write declarative dashboardLinks to agent state dir";
       wantedBy = [ "multi-user.target" ];