refactor(dashboard): regroup launcher icons into 4/4/4 by purpose

Telegram had landed alone on a third row of one icon, with the
first two rows holding a mixed bag (Code next to Email next to
Agenda next to Files next to Music; Feeds next to IRC next to
Slack next to Flashcards next to Books next to Terminal).  No
category showed up grouped, and the asymmetry was bugging me
every dashboard open.

Regroup by what the icons actually do.  Three rows of four:

- Row 1 Work:           Code   / Files       / Terminal / Agenda
- Row 2 Read & Learn:   Feeds  / Books       / Flashcards / Music
- Row 3 Communication:  Email  / IRC         / Slack     / Telegram

Reorder the `define-key' calls on `dashboard-mode-map' to mirror
the row layout -- reading the keymap top-to-bottom now matches
reading the icons left-to-right.

Drive-by fix in the same commit: Music had an icon but no
`dashboard-mode-map' keybinding (mouse-only).  Bound to `m'.

0 files changed, 0 insertions, 0 deletions