Let members forward their club mailbox to their personal email

[AlaqmarG]

Description

• New Email forwarding switch on My profile: forwards the club mailbox to the personal email on the member's account. Off by default.
• Target is always the stored personal email; the request can't name an address. Club addresses and read-only mailboxes can't forward.
• Runs as a per-account Sieve script (forward-to-personal), separate from the co-presidents retirement forward.
• OCI only relays approved senders, so the forwarded copy is From "Sender via BrockCSC" <member@brockcsc.ca> with Reply-To set to the original sender. The mailbox copy is kept untouched.
• Spam isn't forwarded, and an X-BrockCSC-Forwarded header stops forward loops.
• When an approver changes someone's personal email, an active forward follows it (or switches off if it can't).
• Outside production the switch only compiles the script on Stalwart (SieveScript/validate) and doesn't apply it.

Checklist

• npm run typecheck, npm run lint, npm run format:check and npm run build pass
• Schema changes have a committed migration (npm run db:generate) — none
• New env vars added to .env.example, .env.local.example, deploy/docker-compose.yml and komodo/deploy-context.mjs — none
• Admin-only routes gated with requireAdmin / requireApprover — member route, self only
• Tested on the branch's preview deploy (light theme)
• No secrets, internal hostnames or IPs committed
• Live forward verified on production (needs a real inbound message)

Testing Evidence

Email forwarding switched on in the preview (personal details blurred)

• In the preview the switch compiles the rule on the real mail server (SieveScript/validate) without applying it. The first try caught a Stalwart lexer quirk: a quote after an escaped backslash never closes the string. That's fixed in 84e7039, and the rule now compiles.