bump to v0.2.0: complete provider implementation with live-tested DNS record types

- DYNU_API_KEY env var fallback in provider config
- dynu_domain resource: add 9 computed attributes (unicode_name, ipv4/ipv6 flags,
  wildcard aliases, allow_zone_transfer, dnssec, created_on, updated_on)
- dynu_dns_records data source: add 6 type-specific fields (priority, weight,
  port, flags, tag, value)
- Fix normalizeRecordContentForState for MX/SRV/NS/PTR (read host field) and CAA
  (read value field) to avoid plan/state inconsistency
- Allow underscore-prefixed DNS labels in hostname validator (RFC 2782 SRV)
- Preserve plan/state hostname across create/update/read to prevent inconsistent
  result errors when API returns full FQDN for node_name-style records
- Update all version references from 0.1.0 to 0.2.0

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01LFZyrmtKsezBwFWGTWsb2y

internal/provider/provider_integration_test.go

@@ -128,6 +128,20 @@ func TestIntegrationDataSourceDNSRecords(t *testing.T) {
 	if len(state.Records) != 2 || state.Records[0].ID.ValueInt64() != 10 {
 		t.Fatalf("unexpected records state: %#v", state.Records)
 	}
+	for _, rec := range state.Records {
+		if rec.Priority.IsNull() || rec.Priority.IsUnknown() {
+			t.Fatalf("expected priority to be a known value (zero for non-MX), got null/unknown for record %d", rec.ID.ValueInt64())
+		}
+		if rec.Weight.IsNull() || rec.Weight.IsUnknown() {
+			t.Fatalf("expected weight to be a known value, got null/unknown for record %d", rec.ID.ValueInt64())
+		}
+		if rec.Port.IsNull() || rec.Port.IsUnknown() {
+			t.Fatalf("expected port to be a known value, got null/unknown for record %d", rec.ID.ValueInt64())
+		}
+		if rec.Flags.IsNull() || rec.Flags.IsUnknown() {
+			t.Fatalf("expected flags to be a known value, got null/unknown for record %d", rec.ID.ValueInt64())
+		}
+	}
 }
 
 func TestIntegrationDataSourceDiagnosticsFromAPIError(t *testing.T) {