Shell: Tab completes every word of a command, and * and ? stand for several files (#67)

Tab used to complete a command's first word only. It now follows the help
text word by word: `lora st` gives `lora status`, `gnss track ` lists
`start  stop`. The words are read from the help text as written, so a new
command completes with no table to keep; the Shell's own words are added in
the same notation.

`*` and `?` in the last part of a path, for ls, du, rm, cp and mv, from the
Shell and both consoles. The command runs once for each name matched, lined
up and run by the main loop as each finishes; `cancel` empties the line-up.
64 matches at most, refused whole past that. In the Shell, rm with a pattern
asks once, with the count.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

lib/core/src/app_keys.h

@@ -327,6 +327,7 @@ inline constexpr KeyHelp kNotesName[] = {
 inline constexpr KeyHelp kShell[] = {
     {"Enter", "run the line"},
     {"Tab", "complete: a command, a path"},
+    {"* ?", "several files: /notes/*.txt"},
     {"Fn ; .", "lines you typed before"},
     {"Alt ; .", "scroll back, forward"},
     {"Ctrl b", "your replies only, or all"},