> [!IMPORTANT]
> Merging this PR will create a new release.

## Features

* Add background styling to user profile cards
([SableClient#712](SableClient#712) by @nushea)
* Add preventing url preview cards by surrounding a link in
anglebrackets like <https://app.sable.moe>
([SableClient#717](SableClient#717) by @nushea)
* Reorganize Embed settings and reintroduce multiple embeds
([SableClient#667](SableClient#667) by @nushea)
* Change Misc. data styling in users profile pages
([SableClient#663](SableClient#663) by @nushea)
* add initial support for sending discoverable emojis and sticker
([SableClient#730](SableClient#730) by @dozro)

### Themes and tweaks from the catalog
([SableClient#633](SableClient#633) by @7w1)

Themes are pulled from [a repo](https://github.com/SableClient/themes)
now, so you get the full power of CSS instead of a palette. Tweaks are
new: CSS overlays that sit on top of whatever theme you are using.

You'll be prompted to migrate to the new system whenever you update, if
you choose not to, you'll be limited to the basic dark/light themes. A
few additional themes have been added (Rose Pine variantes, Catpuccin)
along with some basic tweaks (circular avatars, monochrome avatars, and
square stuff).

You can share themes and tweaks. For themes uploaded online, simply hit
the copy button in settings and paste the link in chat. If the setting
is enabled, a preview will be generated. Third party themes (as defined
by the config.json) have prominent warning banners and fetching is
disabled by default.

You can also export and share theme files directly, although no previews
are generated for these.

If you're intrested in getting a theme or tweak added to the official
catalog, contribute to the themes repo linked above! We're eager to add
more!

### Markdown parser and render updates
([SableClient#727](SableClient#727) by @7w1)

Migrated markdown parsing and rendering to use marked, which should fix
most (all?) markdown issues involving lists/nested structures,
inconsistent/inaccurate code blocks, escape sequences, and all the other
bugs with literally everything.

Added math rendering support via marked and KaTeX, uses standard `$$`
and `$` delimiters. Only renders a subset of latex tags that will likely
need to be expanded so feel free to make issues if needed.

Also adds support for sending markdown tables (although they're rendered
rather plainly at the moment), sending valid html directly (such as for
colored text), and properly escaping anything with backslashes.

Fixes link previews appearing in code blocks, fixes pmp new line
behavior, fixes links not opening in new tabs, and fixes editing
arbitrary html messages, probably.

Finally, the old WYSIWYG editor has been completely removed.

## Fixes

* Fix spam-clicking abbreviations crashing sable
([SableClient#665](SableClient#665) by @nushea)
* Add cache-control headers in Caddyfile for assets, service worker, and
index.html ([SableClient#609](SableClient#609) by
@Just-Insane)
* Fix the first pin event in a room looking empty
([SableClient#685](SableClient#685) by @nushea)
* Fix read receipt scrolling not working
([SableClient#631](SableClient#631) by @Septicity)
* Fix status sometimes sticking in member tile
([SableClient#664](SableClient#664) by @nushea)
* Fix apng files not animating.
([SableClient#737](SableClient#737) by @7w1)
* Some fixes to sync requests being spammed on loading screen and for
multi-account background syncing, it should also load faster now!
([SableClient#736](SableClient#736) by @7w1)
* Fix other dmed party not being added as a founder by default when
creating a dm. ([SableClient#737](SableClient#737) by
@7w1)
* Update verbiage in the credits
([SableClient#728](SableClient#728) by @nushea)
* spoilered text now gets replaced with `[Spoiler]` in the plain text
fallback, as per MSC4454
([SableClient#715](SableClient#715) by @dozro)
* Hide copied settings links on dynamic rows
([SableClient#695](SableClient#695) by @hazre)
* Fix button hover background smearing in virtual list rows by
suppressing transform on hover
([SableClient#614](SableClient#614) by @Just-Insane)
* Fix Workbox precaching by removing injectionPoint override that was
silently disabling all precache entries
([SableClient#611](SableClient#611) by @Just-Insane)

### Change how settings links are shared
([SableClient#695](SableClient#695) by @hazre)

Settings links copied from Sable now stay on the current client URL and
include a small Sable marker in the link. That lets Sable recognize
settings links copied from other Sable instances without treating
unrelated third-party `/settings/...` links as Sable settings links.

When you send a bare settings link in the composer, Sable now rewrites
it into a labeled link so it looks better on non-Sable clients too. For
example: `[Settings > Account > Display
Name](https://client.example/settings/account?focus=display-name&moe.sable.client.action=settings)`.

Invalid or malformed settings-looking links now stay normal links
instead of being shown as settings chips.

If you previously set `settingsLinkBaseUrl` in `config.json`, remove it.
Sable now derives settings links from the runtime app URL, and the old
config key is no longer used.