docs: say what the CPU prediction path actually does

BraggPrediction.h claimed the buffer "GROWS to whatever a frame actually
predicts, so a large cell is never truncated here". Only the two GPU Calc
overrides call GrowCapacity; both CPU predictors stop at max_reflections.
The cap is applied inside the h/k/l walk and before the resolution test,
so what survives is the low-|h| block, not the reflections nearest the
Ewald sphere - a cell large enough to overflow 20000 gives different
merged reflections with and without a GPU. Documented rather than
silently claimed otherwise.

Also removed a paragraph describing a once-per-predictor overflow warning
that no longer exists, and fixed the rugnux_cli.cpp path in HDF5.md.

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

docs/HDF5.md

@@ -93,7 +93,7 @@ bitshuffle + Zstd; signed integer image datasets use `INTx_MIN` as the HDF5 fill
 
 ### Reprocessing output: `<prefix>_process.h5`
 
-The offline reprocessing tool [`rugnux`](TOOLS.md) (`tools/rugnux_cli.cpp`) re-runs the
+The offline reprocessing tool [`rugnux`](TOOLS.md) (`rugnux/rugnux_cli.cpp`) re-runs the
 full analysis pipeline (spot finding, indexing, refinement, integration, scaling) on an existing
 dataset and writes its results to a master file named **`<prefix>_process.h5`**. This file uses the
 **integrated** format, but instead of copying the images its `/entry/data/data` is a *virtual