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/pages/ConfigPage.tsx

@@ -8,7 +8,7 @@
  *   Jails        — per-jail config accordion with inline editing
  *   Filters      — structured filter.d form editor
  *   Actions      — structured action.d form editor
- *   Server       — server-level settings, logging, database config, map thresholds + flush logs
+ *   Server       — server-level settings, map thresholds, service health + log viewer
  *   Regex Tester — live pattern tester
  *   Export       — raw file editors for jail, filter, and action files
  */
@@ -19,7 +19,6 @@ import {
   ActionsTab,
   FiltersTab,
   JailsTab,
-  LogTab,
   RegexTesterTab,
   ServerTab,
 } from "../components/config";
@@ -55,8 +54,7 @@ type TabValue =
   | "filters"
   | "actions"
   | "server"
-  | "regex"
-  | "log";
+  | "regex";
 
 export function ConfigPage(): React.JSX.Element {
   const styles = useStyles();
@@ -85,7 +83,6 @@ export function ConfigPage(): React.JSX.Element {
         <Tab value="actions">Actions</Tab>
         <Tab value="server">Server</Tab>
         <Tab value="regex">Regex Tester</Tab>
-        <Tab value="log">Log</Tab>
       </TabList>
 
       <div className={styles.tabContent} key={tab}>
@@ -94,7 +91,6 @@ export function ConfigPage(): React.JSX.Element {
         {tab === "actions" && <ActionsTab />}
         {tab === "server" && <ServerTab />}
         {tab === "regex" && <RegexTesterTab />}
-        {tab === "log" && <LogTab />}
       </div>
     </div>
   );