Bring rich composition to LibreMail (issues #36, #37, #38, and #23).
#36 HTML editor + toolbar
- New pure, JVM-testable rich-text model (`richtext/`): RichTextContent with
inline styles + links and block markers ("• ", "N. ", "> "), serializing to a
narrow email-safe HTML subset and back (fromHtml is a faithful inverse).
- Rich editor in ComposeScreen with a bold/italic/underline, bulleted/numbered
list, block-quote, and link toolbar, backed by AnnotatedString. Unformatted
text stays plaintext-only (null HTML) so it feels unchanged and is accessible.
- #23: rounded corners on the compose fields/body via MaterialTheme.shapes.
#37 multipart/alternative + reply/forward quoting
- SmtpSender builds multipart/alternative (text/plain + text/html), nested in
multipart/mixed when there are attachments; GraphSender sends HTML content.
- HtmlToText produces a readable text/plain fallback; ReplyBuilder quotes HTML
originals as clean blockquotes (tags stripped) without corruption.
- HTML body persists/restores through drafts and the outbox (new nullable
bodyHtml columns; Room v9->v10 migration + schema).
#38 signatures
- New signatures table (multiple per account, one default) + repository/DAO;
migration backfills the existing per-account signature as the default.
- Rich signatures reuse the #36 editor; a Signatures management screen (list,
add/edit/delete, set default) is linked from per-account settings.
- The account's default signature auto-inserts on new compose / reply / forward
(honoring the enable toggle), placed above the quote, and stays editable.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>