Merge Log tab into Server tab and remove Log tab

The Log tab provided a service health panel and log viewer. These are
consolidated into the Server tab with a new ServerHealthSection component
that encapsulates all log-related functionality.

- Extract service health panel and log viewer into ServerHealthSection component
- Add severity-based log line color coding (ERROR=red, WARNING=yellow, DEBUG=gray)
- Implement log filtering, line count selection, and auto-refresh controls
- Scroll to bottom when new log data arrives
- Render health metrics grid with version, jail count, bans, failures
- Show read-only log level and log target in health section
- Handle non-file targets with informational banner
- Import ServerHealthSection in ServerTab and render after map thresholds
- Remove LogTab component import from ConfigPage
- Remove 'log' from TabValue type
- Remove Log tab element from TabList
- Remove conditional render for LogTab
- Remove LogTab from barrel export (index.ts)
- Delete LogTab.tsx and LogTab.test.tsx files
- Update ConfigPage docstring

All 115 frontend tests pass (8 fewer due to deleted LogTab tests).

frontend/src/components/config/index.ts

@@ -33,11 +33,11 @@ export { FiltersTab } from "./FiltersTab";
 export { JailFilesTab } from "./JailFilesTab";
 export { JailFileForm } from "./JailFileForm";
 export { JailsTab } from "./JailsTab";
-export { LogTab } from "./LogTab";
 export { RawConfigSection } from "./RawConfigSection";
 export type { RawConfigSectionProps } from "./RawConfigSection";
 export { RegexList } from "./RegexList";
 export type { RegexListProps } from "./RegexList";
 export { RegexTesterTab } from "./RegexTesterTab";
 export { ServerTab } from "./ServerTab";
+export { ServerHealthSection } from "./ServerHealthSection";
 export { useConfigStyles } from "./configStyles";