rugnux report: count overloads and overlapping spots, warn with advice

Overloads: the integrated reflections whose signal disk held a saturated
pixel are counted on the integration outcome before the merge, over the
whole range and over the reflections coarser than 4 A, where they
concentrate (log line "Overloads:", report OVERLOADED_REFLECTIONS*). An
OVERLOADS warning fires from 0.05% of all, or 0.25% of the low-resolution
reflections, and recommends attenuation / a shorter exposure. Measured: a
strongly diffracting in-house sweep reads 0.017% / 0.42% (warned), an
ordinary sweep with a few hundred overloaded partials 0.001% / 0.012%.

Overlaps: both integration engines count the signal disks a nearer
neighbour's prediction takes pixels from (the overlap ownership the default
--overlap exclude already builds), and those left under --overlap-minpk of
their own - BraggIntegrationCounts::overlapped / overlapped_major (log line
"Overlapping spots:", report OVERLAPPED_REFLECTIONS*). An OVERLAPS warning
fires from 1% in the second and recommends a longer distance, finer slicing
or a smaller beam; on 10 battery sets it fires on the two long-axis ones
(8.3% and 13.4%), the rest read 0.0-0.44%. Summary lines for both;
documented in RUGNUX_REPORT.md.

Counters only; nothing reads them. p.mtz md5-identical to the rc175
battery on 10 sets.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SVmAWnzCmRKAXVUCdc4iNi

image_analysis/bragg_integration/BraggIntegrationEngineCPU.cpp

@@ -269,6 +269,11 @@ std::vector<Reflection> BraggIntegrationEngineCPU::RunImpl(const Sampler &img,
                 }
             }
 
+        if (use_owner && n_own < n_disk) {
+            ++counts.overlapped;
+            if (n_own < overlap_min_peak * n_disk) ++counts.overlapped_major;
+        }
+
         int n_bkg_used = n_bkg;   // pixels behind the FINAL background value (trim/clip shrink it)
         // A masked, untrusted, gapped or overloaded pixel inside the signal disk used to discard the
         // reflection outright. A profile fit does not need it to: the fit is the amplitude of a