feat(infra): commit live infra-audit/cluster work to reconcile git with prod

This work (network_hosts inventory + infra_audit MCP tool, /api/cluster +
Sacred Valley cluster card, topbar cluster-health pill + SW self-heal) was
built in an earlier session and DEPLOYED to CT 311 as alpha.24–26, but was
never committed to git — prod was running code absent from the repo. Commits
it as-is (already prod-validated) so git matches the live state, and restores
its alpha.24/25/26 CHANGELOG entries. Files are disjoint from the fold-in
work; both now ship together under alpha.27.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

lib/api/index.js

@@ -32,6 +32,8 @@ import { router as securityRouter } from './routes/security.js';
 import { router as actionsRouter } from './routes/actions.js';
 import { router as littleblueRouter } from './routes/littleblue.js';
 import { router as aiUsageRouter } from './routes/ai_usage.js';
+import { router as infraRouter } from './routes/infra.js';
+import { router as clusterRouter } from './routes/cluster.js';
 
 export function mountApi(app) {
   const api = Router();
@@ -45,6 +47,8 @@ export function mountApi(app) {
   api.use('/spaces/:space_id/companion', companionRouter);
   api.use('/security', securityRouter);
   api.use('/actions', actionsRouter);
+  api.use('/infra', infraRouter);
+  api.use('/cluster', clusterRouter);
   api.use('/little-blue', littleblueRouter);
   api.use('/ai-usage', aiUsageRouter);
   api.use('/projects', projectsRouter);