Replace the single IMAP TLS checkbox with a per-protocol security
dropdown for IMAP, SMTP, and Sieve. The security scheme (ssl:// or
tls://) is now stored directly in the host field, unifying the approach
across all protocols.
Smart form behavior:
- Default ports update automatically when changing security type
- Fields clear on blur when value matches the placeholder
- Warning shown when selecting no encryption
- Defaults: IMAP SSL/993, SMTP STARTTLS/587, Sieve STARTTLS/4190
The DB_SECURE_IMAP_TLS flag is no longer written but still read for
backward compatibility with existing records.
When switching identities, the managesieve plugin still connected to
the default sieve server. Hook into managesieve_connect to redirect
the sieve connection to the remote account's server.
Adds sieve_host, sieve_port and sieve_auth columns to the database,
a Sieve section to the identity settings form, preconfig support for
sieve_host, and localized labels for all 7 languages.
