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

third_party/certspotter/ctclient/static_test.go

@@ -0,0 +1,38 @@
+// Copyright (C) 2025 Opsmate, Inc.
+//
+// This Source Code Form is subject to the terms of the Mozilla
+// Public License, v. 2.0. If a copy of the MPL was not distributed
+// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
+//
+// This software is distributed WITHOUT A WARRANTY OF ANY KIND.
+// See the Mozilla Public License for details.
+
+package ctclient
+
+import (
+	"testing"
+)
+
+func TestFormatTileIndex(t *testing.T) {
+	tests := []struct {
+		in  uint64
+		out string
+	}{
+		{0, "000"},
+		{1, "001"},
+		{12, "012"},
+		{105, "105"},
+		{1000, "x001/000"},
+		{1050, "x001/050"},
+		{52123, "x052/123"},
+		{999001, "x999/001"},
+		{1999001, "x001/x999/001"},
+		{15999001, "x015/x999/001"},
+	}
+	for i, test := range tests {
+		result := formatTileIndex(test.in)
+		if result != test.out {
+			t.Errorf("#%d: formatTileIndex(%q) = %q, want %q", i, test.in, result, test.out)
+		}
+	}
+}