fix(messaging): test email + EmailLog show effective config, not stale env

Two display bugs where admin-facing email diagnostics reported the
.env-level config even when database overrides were in effect — so a
prod admin who switched from SendGrid (.env) to SMTP via /admin/settings
would receive a test email whose body still said "Provider: sendgrid"
and "From: noreply@wizard.lu", even though the actual From header used
the DB-overridden address. Confusing, and erodes trust in the page that
exists specifically to verify the setup.

- admin_settings.send_test_email: read get_effective_email_config(db)
  and display its provider + from_email in the test email's body. Also
  use the effective provider when stamping the audit-log row.
- email_service: in the "template not found" EmailLog branch, record
  the effective from_email / from_name / provider from
  self._platform_config (already populated correctly by __init__),
  instead of falling back to the env-only settings.email_*.

Verified by importing both modules; pure plumbing fix, no schema or
behavior change for callers.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

app/modules/messaging/services/email_service.py

@@ -1317,16 +1317,18 @@ class EmailService:
         if not resolved:
             logger.error(f"Email template not found: {template_code} ({resolved_language})")
             # Create failed log entry
+            # Use the *effective* config so the audit row reflects what the
+            # admin actually configured (DB overrides win over .env).
             log = EmailLog(
                 template_code=template_code,
                 recipient_email=to_email,
                 recipient_name=to_name,
                 subject=f"[Template not found: {template_code}]",
-                from_email=settings.email_from_address,
-                from_name=settings.email_from_name,
+                from_email=self._platform_config.get("from_email", settings.email_from_address),
+                from_name=self._platform_config.get("from_name", settings.email_from_name),
                 status=EmailStatus.FAILED.value,
                 error_message=f"Template not found: {template_code} ({resolved_language})",
-                provider=settings.email_provider,
+                provider=self._platform_config.get("provider", settings.email_provider),
                 store_id=store_id,
                 user_id=user_id,
                 related_type=related_type,