docs: replace the demo gif with an animated SVG of the TUI

Recorded with asciinema against the live network and rendered with
svg-term, so the demo is vector text instead of pixels: 20 KB gzipped
against 400 KB, crisp at any width, and it links through to the site.

README.md

@@ -5,8 +5,6 @@
   </picture>
 </div>
 
-# Soulseek-rs 🦀
-
 **A soulseek client for the terminal. Built for agents and people who live
 there.**
 
@@ -23,7 +21,7 @@ does, how to install it, and every `config.toml` setting.
 
 ## 🎥 Demo
 
-![CLI Demo](fixtures/demo.gif)
+[![soulseek-rs TUI demo](fixtures/demo.svg)](https://re-invention.nl/soulseek-rs/)
 
 ## Features
 
@@ -132,7 +130,7 @@ The one-shot commands follow three rules, so they compose with other tools:
 - **The exit code is the verdict.** No output plus exit 0 never means failure.
 
 | Code | Meaning                                                    |
-| ---- | ------- |
+| ---- | ---------------------------------------------------------- |
 | 0    | success                                                    |
 | 1    | unexpected error                                           |
 | 2    | bad arguments, missing credentials, unusable configuration |
@@ -321,7 +319,7 @@ Every setting can come from a flag, an environment variable, or the config
 file, in that order of precedence. Flags work before or after the subcommand.
 
 | Flag                           | Environment variable                | `config.toml` key            | Default                   |
-| ---- | -------------------- | ----------------- | ------- |
+| ------------------------------ | ----------------------------------- | ---------------------------- | ------------------------- |
 | `--username`                   | `SOULSEEK_USERNAME`                 | `username`                   | required                  |
 | `--password`                   | `SOULSEEK_PASSWORD`                 | never stored in the file     | required                  |
 | `--password-cmd`               | `SOULSEEK_PASSWORD_CMD`             | `password_cmd`               | unset                     |