fix(07): UAT fixes — SMTP test email, DKV routing, Exchange domain field

- SMTP: add test-to field, send real email via sendMail() instead of verify()
- SMTP: fix no_auth warning shown as error for open-relay servers
- DKV: register dkv-fleet in MODULE_REGISTRY (fixes "Modul nicht gefunden")
- DKV: add dynamic [category]/[moduleSlug]/settings + vehicles sub-routes
- DKV: settings/vehicles links use useParams for consistent URLs
- DKV: add gear icon settings link to module main page
- DKV: rename module to "DKV-Rechnung" in seed + translations
- DKV: add optional domain field for Exchange (WebCredentials 3rd arg)
- DKV: hide IMAP-only fields (Port/Verschlüsselung/Ordner) when Exchange selected
- DKV: hide Exchange-only field (Domain) when IMAP selected
- Prisma: add domain column to DkvModuleConfig

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.planning/research/.cache/9fbe9fa057e4989da6badacfc50568bed7d4611e0428fcb135512e5f2f8e770e.json

@@ -0,0 +1 @@
+{"content":"node-ical v0.26.1 is the leading ICS parser for Node.js with 190K weekly downloads. Provides sync/async parsing from strings, files, and URLs. Handles VEVENT, VTODO, VJOURNAL, recurring events, timezones.","source":"web","provider":"websearch","confidence":"MEDIUM","fetched_at":"2026-06-23T12:25:14.159Z","ttl":86400000,"kind":"web"}