feat(domains): per-record provider intel + vendor strip

Structured DNSRecord list carries the detected vendor per row (NS/MX/CNAME/
TXT value, ASN org, response headers, SPF includes, verification strings)
and a Providers strip shows registrar/DNS/hosting/email/CA with favicons —
the domainstack-style view. Detection tables expanded to ~70 NS, ~45 mail,
~60 CNAME, ~130 registrar, and ~50 TXT patterns.

Generated with [Devin](https://devin.ai)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

apps/backend/internal/db/migrations/0011_domain_intel.sql

@@ -0,0 +1,9 @@
+-- +goose Up
+-- Structured DNS records + provider identifications for the domain detail
+-- page. JSON blobs — the flat columns stay for compat and check history.
+ALTER TABLE domains ADD COLUMN records   TEXT NOT NULL DEFAULT '[]';
+ALTER TABLE domains ADD COLUMN providers TEXT NOT NULL DEFAULT '{}';
+
+-- +goose Down
+ALTER TABLE domains DROP COLUMN providers;
+ALTER TABLE domains DROP COLUMN records;