Adds the universal "send with the platform modifier" shortcut every
mainstream mail client (Gmail, Outlook, Apple Mail, Proton, Tutanota,
Fastmail, Thunderbird) supports. Closes#343.
Behaviour:
* Window-level keydown listener registered while the composer is
mounted. Fires when focus is anywhere inside the composer — chip
inputs, subject, body textarea, or the rich-text contentEditable.
* Plain Enter is untouched; only Enter + Ctrl (Win/Linux) or Cmd
(macOS) triggers send. Shift/Alt modifiers are ignored so existing
autocomplete-confirm / chip-commit Enters are not hijacked.
* Routes through a ref so handleSend's per-render rebind doesn't
re-register the listener every render.
* All existing send-time validation, attachment-warning, draft-save
and undo-send flows still apply — the shortcut just calls the
same handleSend() as the toolbar button.
* Listed in the Keyboard Shortcuts dialog under the existing
Composer section.
Tested:
* Compose -> type body -> Ctrl+Enter -> Outbox.
* Cc/Bcc autocomplete suggestion + Enter still selects (alt-free
Enter without Ctrl, so the new listener bails).
* Subject input -> Ctrl+Enter -> sends.
* Body Enter without modifier -> newline.
* Added account selection for protocol links when multiple connected accounts are available, including mailto: links
* Added support for handling mailto: links in an already-open PWA/session instead of always opening a new tab
* Added webcal: protocol handling for calendar links
* Added account selection for webcal: links when multiple calendar-capable accounts are connected
* Added an import-or-subscribe choice for detected webcal calendars
* Added protocol handler settings for registering mail and calendar handlers and choosing the open mode
* Added service worker/session coordination for passing protocol requests between browser/PWA contexts
* Added tests and translations for the new protocol handler flows
Adds an Override toggle in the composer's From row. When enabled, name
and address become free-text inputs. Mail is still submitted through the
selected identity, but the outgoing message's From: header — and the
SMTP envelope MAIL FROM when different — is set from the override.
The existing "Auto-select Reply Address" setting is extended: if the
incoming message was addressed to an alias on a domain that matches one
of your identities but isn't itself an identity (classic domain catch-
all), it now auto-enables Override and pre-fills the alias. Quick reply
honors the same resolution. The setting is relabeled to reflect the
broader behavior.
JMAP: client.sendEmail gains an optional envelopeMailFrom; when set, the
EmailSubmission includes an explicit envelope with that mailFrom and the
to/cc/bcc as rcptTo so header-From and envelope can diverge (JMAP §7.3).
S/MIME: override is incompatible with sign/encrypt and is refused with a
clear error — signing a different visible From from the identity's
certificate Subject would produce messages clients reject.
Tests: resolveReplyFrom covers exact match, sub-address stripping,
catch-all detection, identity preference, and foreign-domain null.
Linus Rath