ctcloud: CertSpotter-backed CT cloud-resource monitor

Single stateless Go process that consumes CT logs via embedded (patched)
CertSpotter internals, classifies cloud/database/storage DNS identifiers
in-process with a zero-allocation classifier, enriches via round-robin DNS
resolvers with CNAME following, and batch-writes useful findings to PostgreSQL.

- third_party/certspotter: 2-hunk IdentifierSink patch, no stdout/JSON/files
- internal/classify: AWS/Azure/GCP/Firebase/Cloudflare R2/DigitalOcean/Supabase/OCI
- internal/dns: sharded bounded TTL cache, multi-resolver load balancing + failover
- internal/pipeline: bounded queues, dedup, direct-priority load shedding
- internal/store: pgx batch writer, Postgres CT checkpoints (no cert contents)
- internal/probe: optional non-destructive reachability checks (off by default)
- Docker: distroless non-root, read-only rootfs, no app volume, resource limits
- tests enforce 0 allocs/op on the classifier and sink hot path

internal/classify/digitalocean.go

@@ -0,0 +1,39 @@
+package classify
+
+import "tea.karlcom.de/karl/bucketeer/internal/model"
+
+// classifyDigitalOceanSpaces handles
+// <bucket>.<region>.digitaloceanspaces.com and the cdn variant.
+func classifyDigitalOceanSpaces(s *scanner) (model.Match, bool) {
+	n := s.n
+	if s.label(n-1) != "com" || s.label(n-2) != "digitaloceanspaces" {
+		return model.Match{}, false
+	}
+	// <bucket>.<region>.digitaloceanspaces.com (n==4) or the cdn variant (n==5)
+	if n != 4 && !(n == 5 && s.label(2) == "cdn") {
+		return model.Match{}, false
+	}
+	bucket := s.label(0)
+	region := s.label(1)
+	return model.Match{
+		Provider:         model.ProviderDigitalOcean,
+		Service:          model.ServiceObjectStorage,
+		ResourceSpecific: true,
+		Region:           region,
+		Resource:         bucket,
+	}, true
+}
+
+// classifyDigitalOceanDB handles <name>.db.ondigitalocean.com.
+func classifyDigitalOceanDB(s *scanner) (model.Match, bool) {
+	n := s.n
+	if n < 4 || s.label(n-1) != "com" || s.label(n-2) != "ondigitalocean" || s.label(n-3) != "db" {
+		return model.Match{}, false
+	}
+	return model.Match{
+		Provider:         model.ProviderDigitalOcean,
+		Service:          model.ServiceDatabase,
+		ResourceSpecific: true,
+		Resource:         s.label(0),
+	}, true
+}