fix: various small fixes and improvements

- Add 'skipped' to authentication result enum in OpenAPI spec
- Fix optional chaining on bimiResult.details check
- Add rbls field to AppConfig interface
- Restrict theme storage to valid 'light'/'dark' values only
- Fix null coalescing for blacklist result data
- Fix survey source to use domain instead of ip

web/src/lib/components/SummaryCard.svelte

@@ -331,7 +331,7 @@
                     highlight: { color: "good", bold: true },
                     link: "#dns-bimi",
                 });
-                if (bimiResult.details && bimiResult.details.indexOf("declined") == 0) {
+                if (bimiResult?.details && bimiResult.details.indexOf("declined") == 0) {
                     segments.push({ text: " declined to participate" });
                 } else if (bimiResult?.result === "fail") {
                     segments.push({ text: " but " });