console: each command carries its summary, and dispatch names it, -166 B

The help text was thirteen help_row(N) calls and the dispatch thirteen
case N labels, both counting positions in a list defined elsewhere. A
command is now one row of name and summary; the summaries become a second
NUL-separated flash blob printed in a loop, and every case label is
command_index("name"), which does not compile for a name the list lacks.
The help column derives from the longest name, the dotted padding is one
helper for labels and help rows alike, and the ADC scale, the monitor
interval and the uptime units are named. Output is unchanged; the image
goes from 8004 B to 7838 B, both modes byte-identical. The 32-bit
narrowing in dev/tasks.md is re-measured against the new image.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -66,7 +66,7 @@ cmake --preset atmega328p-generated
 cmake --build --preset atmega328p-generated
 ```
 
-The firmware is **8004 B** of flash, byte-identical between the generated and
+The firmware is **7838 B** of flash, byte-identical between the generated and
 reflect modes, and `ctest` holds it to that number.
 
 ## Atmel Studio