Command filter: multi-select with conversation presets (v2.7.0)

- the single-command <select> becomes a checkbox dropdown: the filter is a
  set of entries (an empty set shows everything), so any number of commands
  can be shown at once instead of one
- three fixed presets select whole conversations:
  * Proactive sessions — FETCH, TERMINAL PROFILE and every command the card
    answered with SW 91xx (the proactive-session initiators)
  * Proactive + events — the same plus ENVELOPE
  * File operations — SELECT, READ BINARY, READ RECORD, UPDATE BINARY,
    UPDATE RECORD (their GET RESPONSE, which carries the data/FCP, comes
    along through the existing response_for linkage)
  presets and single commands combine as a union, and the menu lists the
  session's commands with their counts
- the button summarises the selection ("All commands" / one name /
  "{n} commands"); Escape or a click outside closes the menu; focusing an
  APDU from the Files panel/map still clears the filter first
- tests: a new filter test (the matching rules per entry kind, the GR
  linkage, the presets, the union, the summary, the menu rows, the RU keys
  and the wiring pins), and the focusMessage tests follow the new state;
  527 Python + 72 Node tests
- README/README_RUS describe the filter; PWA_VERSION/pyproject/version.py
  2.7.0, SW cache simtrace-analyser-v80

README.md

@@ -71,7 +71,12 @@ GSMTAP into this analyser.
   and AUTH commands get distinctive styling in map view
 - Sessions with deep links (`#session=N`), PCAP import (`.pcap/.pcapng/.cap`),
   COMPRION trace import (the Device Manager *ISO Protocol Layer* text export),
-  search and type filtering
+  search and a **multi-select command filter** — pick any number of commands
+  and/or the conversation presets (*Proactive sessions*: FETCH, TERMINAL
+  PROFILE and every command answered with SW 91xx; *Proactive + events*: the
+  same plus ENVELOPE; *File operations*: SELECT, READ/UPDATE BINARY and
+  READ/UPDATE RECORD, with the GET RESPONSE carrying a selected command's
+  data)
 - Installable PWA, dark theme, English/Russian UI
 
 ## Prerequisites