broker: bootstrap a concrete max_hkl, as the API and the docs already claim

How far the predictor walks the lattice became a setting defaulting to "derive it from
the refined cell", which is what is wanted offline. Online it is not: per-image
prediction cost then depends on whichever crystal is mounted, and the cube (2n+1)^3
grows quickly. The broker was only ever handed a concrete value when a client sent a
bragg_integration block, and none of the shipped configs has one, so the derived path
was the normal deployment.

Four places in the tree - the conversion, the predictor, the OpenAPI description and the
changelog - already state that the broker keeps a fixed bootstrap. Make that true.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

broker/JFJochBrokerParser.cpp

@@ -179,6 +179,13 @@ void ParseFacilityConfiguration(const org::openapitools::server::model::Jfjoch_s
 
     if (j.braggIntegrationIsSet())
         experiment.ImportBraggIntegrationSettings(Convert(j.getBraggIntegration()));
+    else
+        // A config with no bragg_integration block still has to bootstrap a concrete max_hkl, or the
+        // predictor falls back to deriving the hkl cube from the refined cell and a live acquisition's
+        // per-image cost is decided by whichever crystal is mounted. None of the shipped configs sets
+        // the block, so this is the normal path online.
+        experiment.ImportBraggIntegrationSettings(
+                BraggIntegrationSettings().MaxHKL(BRAGG_ONLINE_DEFAULT_MAX_HKL));
 
     if (j.darkMaskIsSet())
         experiment.ImportDarkMaskSettings(Convert(j.getDarkMask()));

common/BraggIntegrationSettings.h

@@ -12,6 +12,10 @@
 // spots - see docs/CPU_DATA_ANALYSIS.md (Bragg integration).
 enum class IntegratorMode { BoxSum, ProfileGaussian, ProfileEmpirical };
 
+// The hkl half-width the broker bootstraps when a config carries no bragg_integration block. Matches
+// the max_hkl default in broker/jfjoch_api.yaml, so an omitting client and an omitting config agree.
+constexpr int BRAGG_ONLINE_DEFAULT_MAX_HKL = 100;
+
 class BraggIntegrationSettings {
     IntegratorMode integrator_mode = IntegratorMode::ProfileGaussian;
     float r_1 = 4;
@@ -39,6 +43,8 @@ class BraggIntegrationSettings {
     //
     // Unset (the default) means "take it from the refined cell", which is exact: the predictor keeps
     // only |q| <= 1/d_min and h = a.q, so no reflection can have |h| > a/d_min. See MaxHKLForCell.
+    // Offline that is what is wanted. ONLINE it is not: the broker bootstraps a concrete value
+    // (BRAGG_ONLINE_DEFAULT_MAX_HKL) so per-image cost stays predictable across samples.
     std::optional<int> max_hkl;
 
 public: