v1.0.18-debug

Debug build. NOT runtime-verified on-device (no install performed; sideload manually). Compile-verified + evidence-backed.

Fixes:

1. IMAP port box off-center (AddAccountScreen AdvancedServerFields): a fillMaxWidth()
   Surface lived inside the weight(1f) port Row -> moved to its own full-width Row.
2. Calendar sync OFF by default: AddAccountScreen overrode SyncConfig.Defaults() with
   syncCalendar = calUrl != null, and calUrl was blank (autodiscover/mailcow never fills
   it). Now mailcow accounts prefill the EXACT SOGo URL (.../SOGo/dav//Calendar/personal/)
   and all sync legs default ON.
3. Biometric prompt crashed/didn't show (MainActivity): setNegativeButtonText() together
   with DEVICE_CREDENTIAL in allowed authenticators -> PromptInfo.build() threw
   IllegalArgumentException. Removed the negative button when credential fallback is offered.
4. Email sync reported failure (items=0) even though INBOX synced: 30s IMAP socket timeout
   killed the large Sent fetch (log: Couldn't connect... timeout 30000). Raised timeouts
   (conn 60s, read 300s, write 120s) and made a partial sync (>=1 folder synced) report
   success so synced mail is not masked by one slow folder.

Still TODO (pending your go-ahead):

• Port Hearthboard's CalDAVClient into UnifiedComms for extra SOGo/Nextcloud robustness
  (current UnifiedComms client already handles SOGo directly; calendar likely works now).
• Deep-dive email-display if mail is still invisible after a successful sync.
• Adapt UnifiedComms' email function INTO Hearthboard (cross-repo, later).