broker: serve the placed model and its maps of the last rugnux live run (/rugnux/model.cif, /rugnux/map.ccp4)

A rugnux live run that placed a model keeps it, with a copy of its map coefficients, beside the live
status (RugnuxStructure), for as long as /rugnux/status keeps the run. Made in memory on the first
request and cached, never written to disk:
- GET /rugnux/model.cif: the placed model as mmCIF, labelled as WritePlacedModel labels _model.cif
  (PlacedModelMmcif, the labelling factored out of WritePlacedModel; the file output is unchanged).
- GET /rugnux/map.ccp4?type=2fofc|fofc: the 2mFo-DFc / mFo-DFc map as a CCP4 map, FFT of the
  FWT/PHWT or DELFWT/PHDELWT coefficients (get_f_phi_on_grid + MapFromFPhi, sampled as ModelValidation
  samples), cut to the box around the model plus 5 A, with the whole cell's mean and RMS in the header.
- 404 without a placed model or maps, 400 for an unknown map type; both routes protected by the dataset
  bearer token like /rugnux/status. rugnux_live_status gets placed_model.

C++ model, python client docs, TypeScript client and redoc regenerated.

Tests: a point's coefficients give a map peaking at the atom in a cropped box; the mmCIF; the structure
is cleared at the next start; the auth test covers the new routes. End to end (myoglobin 2M replay with
an AlphaFold model): the maps equal gemmi's FFT of the written _maps.mtz to 2.5e-6 rms.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015CeEGgpKdfkCTJb3YNMJcu
(cherry picked from commit 33124c3288ba112def3f51c0d91f5206886f3495)

tests/BrokerHttpAuthTest.cpp

@@ -70,7 +70,7 @@ TEST_CASE("JFJochBrokerHttp_BearerTokens", "[broker]") {
                                 "/image_buffer/image.cbor?id=0", "/image_buffer/image.tiff?id=0",
                                 "/image_buffer/image.jpeg?id=0", "/preview/plot?type=bkg_estimate",
                                 "/preview/plot.bin?type=bkg_estimate", "/live/events",
-                                "/rugnux/status"}) {
+                                "/rugnux/status", "/rugnux/model.cif", "/rugnux/map.ccp4?type=2fofc"}) {
             INFO(path);
             auto res = client.Get(path);
             REQUIRE(res);
@@ -93,6 +93,11 @@ TEST_CASE("JFJochBrokerHttp_BearerTokens", "[broker]") {
         REQUIRE(client.Get("/statistics/data_collection", other)->status == 200);
         REQUIRE(client.Get("/preview/plot?type=bkg_estimate", good)->status == 200);
         REQUIRE(client.Get("/rugnux/status", good)->status == 200);
+        // No live run placed a model: nothing to serve, but the token is accepted.
+        REQUIRE(client.Get("/rugnux/model.cif", good)->status == 404);
+        REQUIRE(client.Get("/rugnux/map.ccp4", good)->status == 404);
+        REQUIRE(client.Get("/rugnux/map.ccp4?type=fofc", good)->status == 404);
+        REQUIRE(client.Get("/rugnux/map.ccp4?type=anomalous", good)->status == 400);
     }
 
     SECTION("the aggregate statistics drop the measurement block instead of refusing") {