Files view: drop the ASCII column from the change-details hex views

- the modal's hex views carried a 16-byte ASCII column per row; file data is
  rarely text and the column halved the room for the two before/after views,
  so it is gone: `hexImageRows` no longer builds an `ascii` field,
  `hexImageHtml` no longer emits it and the `.hex-ascii` CSS rule is removed
- tests: the hex-row test asserts the field is gone (so it cannot come back
  silently); README/README_RUS wording updated
- SW cache simtrace-analyser-v67 (cosmetic, no version bump)

README.md

@@ -196,9 +196,9 @@ a row jumps to the APDU in the trace.  Rows that carry a recorded change (a
 card-side change, or an update that wrote or first observed bytes) also offer
 **Details**: a modal showing the affected unit — the whole file, or the single
 record that changed — **before and after** the change, as hex views (16 bytes
-per row with an ASCII column, never-observed bytes drawn as `--`) with the
-bytes that changed highlighted in one colour and the bytes the operation first
-observed in another, plus the changed/new byte counts and the APDU reference.
+per row, never-observed bytes drawn as `--`) with the bytes that changed
+highlighted in one colour and the bytes the operation first observed in
+another, plus the changed/new byte counts and the APDU reference.
 
 The images come from `GET /api/sessions/<id>/files/image?key=…&change=…` and
 are reconstructed from the current image by undoing the later changes