Themes for the terminal and the web

One theme format now styles the terminal and the web together, with five bundled themes and an editor for your own. Interviews ask in rounds instead of one question at a time.

Added

Themes restyle the terminal and the web UI together, with trau, Catppuccin, Dracula, Gruvbox and Nord in Settings → Appearance
A built-in theme editor previews colors live, saves themes on this machine and exports them to share
Opt-in stacked pull requests chain an epic’s slices as a native GitHub stack, with no epic branch to merge at the end
Chromium browsers can install the web UI as an app

Changed

Interviews ask each round of questions as one numbered form, so a session takes a handful of round-trips instead of twenty

Fixed

Jira blocker and blocked links that trau creates now point the right way