Remove residual sample identities missed by the earlier scrub

The rc.160 sample-identity cleanup left protein names, internal dataset
codes, and a measured cell angle in several source comments and one test.
Most sensitive: a measured monoclinic beta tied to an internal code in
Rugnux.cpp and IndexAndRefine.cpp. Rewrite each to describe the
crystallographic situation only (space group / metric relation), keeping
the technical reasoning intact. Comment- and string-only; no behaviour
change. (rugnux_cli.cpp's remaining name is scrubbed in the following
commit, alongside its other change to that file.)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/SearchSpaceGroupTest.cpp

@@ -150,7 +150,7 @@ TEST_CASE("SearchSpaceGroup detects synthetic space groups") {
 
 // Regression: a real screw axis whose systematically-absent reflections carry a genuinely weak
 // intensity but an UNDER-estimated sigma (so their I/sigma clears the "present" cut) must still be
-// found. Reproduces the monoclinic 2_1 miss on EP_cs_02-10 / EP_cs_01-17, where the merged sigmas on
+// found. Reproduces a monoclinic 2_1 miss on weakly-diffracting monoclinic data, where the merged sigmas on
 // the 0k0-odd reflections were ~2x too small and faked screw-axis violations. The E^2 intensity gate
 // (present_e_squared) is what keeps those reflections classified absent.
 TEST_CASE("SearchSpaceGroup finds a screw axis despite under-estimated sigmas on absent reflections") {