This release rolls together everything since 1.5.7 — the headline
items are the Manifest V3 migration and a new "Add to Proton
Calendar" action for inbound calendar attachments.

New
• Add to Proton Calendar: emails with .ics attachments (flight
confirmations, hotel bookings, meeting invites…) now show an
"Add to Proton Calendar" button. Multiple .ics per email each
get their own card. If you have several calendars, a picker
lets you choose; the default calendar is preselected. Once an
event is saved, the button switches to "Open in Proton
Calendar" and deep-links to the event's day.
• Persistent Add-account form: typing a username then closing
the popup no longer loses your progress. The username is
restored on next open; the password is never stored.

Improvements
• Faster popup after idle: the message list is cached in
session storage so reopening the popup no longer shows
"Checking mail…" for several seconds.
• Cleaner CAPTCHA flow: the CAPTCHA tab closes itself on
success and the popup reopens with the next step automatically.
• Theme & color-scheme selection applies correctly on popup
open — no more brief "classic" flash.
• Calendar invite cards: tighter layout, primary action
prominent, Open-in-Mail demoted to an icon button.
• Premium-only options properly locked on the free tier from
page load.

Under the hood
• Migrated to Manifest V3. The extension uses
declarativeNetRequest in place of blocking webRequest for the
CAPTCHA flow's CSP relaxation; webRequestBlocking permission
removed.

Fixes
• Multi-address account: "Add to Calendar" picks the correct
signing address key for shared calendars and custom-domain
accounts.
• FIDO2 / CAPTCHA tabs now close reliably on Chrome too.