Unifies the two previously independent email subsystems — MailService
(net/smtp transport) and NotificationService (HTTP-based providers) —
so email can participate in the notification dispatch pipeline.
Key changes:
- SendEmail signature updated to accept context.Context and []string
recipients to enable timeout propagation and multi-recipient dispatch
- NotificationService.dispatchEmail() wires MailService as a first-class
provider type with IsConfigured() guard and 30s context timeout
- 'email' added to isSupportedNotificationProviderType() and
supportsJSONTemplates() returns false for email (plain/HTML only)
- settings_handler.go test-email endpoint updated to new SendEmail API
- Frontend: 'email' added to provider type union in notifications.ts,
Notifications.tsx shows recipient field and hides URL/token fields for
email providers
- All existing tests updated to match new SendEmail signature
- New tests added covering dispatchEmail paths, IsConfigured guards,
recipient validation, and context timeout behaviour
Also fixes confirmed false-positive CodeQL go/email-injection alerts:
- smtp.SendMail, sendSSL w.Write, and sendSTARTTLS w.Write sites now
carry inline codeql[go/email-injection] annotations as required by the
CodeQL same-line suppression spec; preceding-line annotations silently
no-op in current CodeQL versions
- auth_handler.go c.SetCookie annotated for intentional Secure=false on
local non-HTTPS loopback (go/cookie-secure-not-set warning only)
Closes part of #800
