docs: a README with a face, in English and Portuguese; decode every HTML entity in previews

The README opens like a product page: the mark, a line on what it is, the
links, the language switch and a picture of the real interface running on an
invented mailbox, in dark and light and in both languages. scripts/screenshots
holds that invented mailbox and the script that photographs it, so the pictures
can be redone. Previews now decode any HTML entity through the browser rather
than a short list, so a Portuguese or marketing preview no longer prints
ç or ·.

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

README.md

@@ -1,7 +1,18 @@
-# LambdaMail
+<p align="center"><img src="docs/img/lambdamail-logo.svg" width="120" alt="LambdaMail"></p>
+<h1 align="center">LambdaMail</h1>
+<p align="center">Your own mail server, with a webmail that is a pleasure to use.<br>SMTP, IMAP and POP3 · SPF, DKIM, DMARC and ARC · Webmail and admin console · One <code>docker-compose.yaml</code>, made for Coolify.</p>
 
-A self-hosted mail server with an integrated webmail and admin console, built to
-run on [Coolify](https://coolify.io) from a single `docker-compose.yaml`.
+<p align="center"><a href="docs/WEBMAIL.md">Webmail</a> · <a href="docs/DEPLOYMENT.md">Deploying</a> · <a href="docs/OPERATIONS.md">Operating</a> · <a href="docs/MAILBOX-CORE.md">Mailbox core</a> · <a href="LICENSE">License</a></p>
+
+<p align="center"><b>English</b> · <a href="README.pt-BR.md">Português</a></p>
+
+<p align="center"><img src="docs/img/webmail-dark-en.png" width="900" alt="The LambdaMail webmail in the dark theme: the inbox as conversations on the left, and the Launch checklist conversation open on the right with the newest message expanded and the older ones as a line each"><br><sub>The real interface running on an invented mailbox: names, addresses and messages are made up.</sub></p>
+
+---
+
+LambdaMail is a self-hosted mail server with an integrated webmail and admin
+console, built to run on [Coolify](https://coolify.io) from a single
+`docker-compose.yaml`.
 
 SMTP, IMAP, POP3 and ManageSieve, with SPF, DKIM, DMARC, ARC, MTA-STS and
 TLS-RPT, DNS automation through Cloudflare, and spam and virus filtering. No
@@ -12,8 +23,6 @@ paid tiers and no artificial limits on domains or mailboxes.
 > See [What is not finished](#what-is-not-finished) before putting real mail
 > through it.
 
----
-
 ## What it does
 
 | Area | |
@@ -84,6 +93,11 @@ The reference is **[docs/WEBMAIL.md](docs/WEBMAIL.md)**. The short version:
 | `c` | New message |
 | `/` | Search the list |
 
+<p align="center"><img src="docs/img/webmail-light-en.png" width="440" alt="The same conversation in the light theme"> <img src="docs/img/designed-light-en.png" width="440" alt="A designed newsletter keeping its own white sheet, in the light theme"></p>
+<p align="center"><sub>The light theme, and a designed message (a newsletter, a receipt) that keeps the sheet it was drawn for. A message written plainly takes the app's own colours instead.</sub></p>
+
+<p align="center"><img src="docs/img/menu-dark-en.png" width="620" alt="The command menu open over a conversation, listing actions, folders and appearance"><br><sub>The command menu, on <code>Ctrl K</code> or <code>Cmd K</code>.</sub></p>
+
 ## Deploying
 
 For a real VPS, follow **[docs/DEPLOYMENT.md](docs/DEPLOYMENT.md)**. It covers the
@@ -161,6 +175,10 @@ make seed                            # a postmaster@example.test fixture
 The webmail is on `http://localhost:3000`. The seeded password is
 `dev-password-only` — it is a fixture, not a credential.
 
+To see or work on the interface without any mail services, run the invented
+mailbox in [`scripts/screenshots/`](scripts/screenshots/README.md) and point the
+webmail at it; the same stub produced the pictures above.
+
 ## Testing
 
 ```bash