Security fixes:
- Escape plain text body to prevent XSS via trustAsHtml
- Add SSRF protection to image proxy (block private IPs, require auth)
- Sanitize Content-Disposition filename to prevent header injection
- Escape Sieve script values to prevent script injection
- Escape IMAP search query to prevent search injection
Install/upgrade fixes:
- Move setupWebmail() call to after Dovecot is installed (was running
before doveadm existed, silently failing on every fresh install)
- Make setupWebmail() a static method callable from install.py
- Fix upgrade idempotency: always run dovecot.conf patching and
migrations even if webmail.conf already exists (partial failure recovery)
Frontend fixes:
- Fix search being a no-op (was ignoring results and just reloading)
- Fix loading spinner stuck forever on API errors (add errback)
- Fix unread count decrementing on already-read messages
- Fix draft auto-save timer leak when navigating away from compose
- Fix composeToContact missing signature and auto-save
- Fix null subject crash in reply/forward
- Clear stale data when switching accounts
- Fix attachment part_id mismatch between parser and downloader
Backend fixes:
- Fix Sieve _read_response infinite loop on connection drop
- Add login check to apiSaveDraft