docs: a large spindle-to-symmetry-axis angle does not clear the mounting

The paragraph introduced with the two new report keys said an incomplete cusp
could be "attributed to the mounting or cleared of it". The first half holds;
the second does not. A symmetry axis within theta_max of PERPENDICULAR to the
spindle carries the blind cone onto its opposite lobe, which a sweep leaves
equally unmeasured, so a large angle is not on its own evidence that the
mounting was harmless - and the key reports only the nearest axis.

Also record the two keys in the changelog, and correct REPORT_VERSION there:
the entry still said 6 after the bump to 7.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EFEJG6WBQv8th4UJFNe53N

docs/CHANGELOG.md

@@ -14,7 +14,8 @@
 * `rugnux` writes the unmerged MTZ by default, with a P1 merge beside it, a batch header for every image the observations span, and events kept to the same `--min-captured-fraction` as the merge, so a wrong space group can be re-merged in a scaling program without reprocessing.
 * `rugnux` decides which partials belong to one rocking event from an angle rather than a frame count, so a coarsely sliced sweep no longer joins two crossings of the Ewald sphere into a single full reflection.
 * `rugnux` writes reflection files in the conventions downstream programs read: `FreeR_flag` is 0 for the test set and 1 for the working set - it was the other way round - the merged and P1 MTZ carry the reserved `HKL_base` dataset so a CCP4 program reads the wavelength instead of falling back to 1.54187 A, and the merged mmCIF marks the free set as `_refln.status` = `f`.
-* The rugnux results report carries the space groups the data cannot separate and the enantiomorph state, the model's verdict and what it was allowed to decide, the detector geometry measured and what a single sweep cannot determine, the resolution the CC1/2 fit reached, which reciprocal axis each anisotropic diffraction limit belongs to, and twinning measured before and after the space group was decided; `REPORT_VERSION` is 6, and `SPACE_GROUP_ENANTIOMORPH= DETERMINED_FROM_MODEL` is now `ASSUMED_FROM_MODEL`.
+* The rugnux results report carries the space groups the data cannot separate and the enantiomorph state, the model's verdict and what it was allowed to decide, the detector geometry measured and what a single sweep cannot determine, the resolution the CC1/2 fit reached, which reciprocal axis each anisotropic diffraction limit belongs to, and twinning measured before and after the space group was decided; `REPORT_VERSION` is 7, and `SPACE_GROUP_ENANTIOMORPH= DETERMINED_FROM_MODEL` is now `ASSUMED_FROM_MODEL`.
+* The rugnux results report records how the crystal sat on the goniometer as `SPINDLE_SYMMETRY_AXIS_ANGLE_DEG=` and `SPINDLE_SYMMETRY_AXIS_ORDER=` - the angle from the spindle to the nearest symmetry axis and that axis's order - on every rotation run that determined a space group, not only when the angle was small enough to warn about.
 * `rugnux --mode calibration` writes `<prefix>.json` beside the `.poni`, holding the geometry as a `jfjoch_broker` `dataset_settings` body, and refuses a fit that is not a measurement - no `.poni`, a non-zero exit, `converged` recorded in the `.json`; `--no-refine-tilt` holds the detector tilt at the file's value instead of zeroing it.
 * A snake grid scan with a negative slow step and an even number of rows no longer has its positions mirrored along the fast axis in the HDF5 master and the grid map, so the positions recorded for that configuration change; `jfjoch_viewer` draws grid scan cells in the proportion of the scan steps, labels the merge-statistics plot over the range the axis is drawn on, and builds its powder-calibration ring list from the loaded dataset's space group as well as its cell, so a centred sample cell no longer scales the whole fit.
 * The HDF5 master records `direct_beam_x`/`direct_beam_y` - where the undeflected beam lands, sent on the CBOR start message too - the beam size at the sample as `incident_beam_size` from the new `dataset_settings` `beam_size_x_um`/`beam_size_y_um`, and `/entry/MX/peakCountUnfiltered`; `dataset_settings` accepts any `smargon.chi_deg`, which was restricted to 0-90 degrees.

docs/RUGNUX_REPORT.md

@@ -246,8 +246,10 @@ sat on the goniometer: the angle between the spindle and the nearest symmetry ax
 order. Below about 15 deg the axis maps the sweep's blind cone onto itself and the reflections in
 that cone stay missing however long the sweep runs, which is why the same number also raises a
 warning there. It is written on every rotation run that determined a space group, including the
-ordinary well-mounted case, so an incomplete cusp can be attributed to the mounting or cleared of it.
-(New in `REPORT_VERSION= 7`.)
+ordinary well-mounted case, so an incomplete cusp can be attributed to the mounting. A large angle
+does not on its own clear it: an axis within the same margin of perpendicular to the spindle carries
+the blind cone onto its opposite half, which is equally unmeasured, and only the nearest axis is
+reported. (New in `REPORT_VERSION= 7`.)
 
 `SPACE_GROUP_ENANTIOMORPH=` in section 4 reads **`ASSUMED_FROM_MODEL`** when the hand written in the
 files is the model's. Assumed, not determined: merged intensities cannot see the hand at all — |F| is