EXPERIMENTAL: replace KV-scan consensus with Autobase sidecar engine

Cut over domain resolution to an Autobase apply-based sidecar fed by
claim/vote dual-writes from dnsPass. Remove the legacy full-KV scan
getConsensusState path and wire all reads through consensus-view.

- Add consensus-resolver, consensus-events, consensus-apply,
  consensus-autobase, and consensus-view modules
- Dual-append consensus events on claim/vote dnsPassAdd/Remove
- Bootstrap sidecar from existing KV entries; persist
  consensusAutobaseKey in network manifest
- Expose sidecar health via GET /api/consensus/status and metrics
- Add consensus-resolver and consensus-apply unit tests
- Expand RFC 0001 to Implemented; update CONSENSUS.md

Rollback: deploy prior release; KV data unchanged, sidecar rebuilds on
next startup.

includes/admin/admin-backend/routes/consensus.js

@@ -10,6 +10,25 @@ async function handleConsensusRoutes(req, res) {
   const method = req.method;
   const url = new URL(req.url, `https://${req.headers.host}`);
 
+  // GET /api/consensus/status - Sidecar health
+  if (method === 'GET' && urlPath === '/api/consensus/status') {
+    try {
+      trackRequest('/api/consensus/status', true);
+      const { getConsensusStatus } = require('../../../core/consensus-autobase');
+      const status = getConsensusStatus();
+      res.writeHead(200, { 'Content-Type': 'application/json' });
+      res.end(JSON.stringify(status));
+      return true;
+    } catch (err) {
+      logError('Consensus', `Failed to get consensus status: ${err.message}`);
+      trackRequest('/api/consensus/status', false);
+      const errorResponse = createErrorResponse(err, 500);
+      res.writeHead(errorResponse.statusCode, errorResponse.headers);
+      res.end(errorResponse.body);
+      return true;
+    }
+  }
+
   // GET /api/consensus/metrics - Get consensus metrics
   // Check this BEFORE the domain route to avoid matching "metrics" as a domain
   if (method === 'GET' && urlPath === '/api/consensus/metrics') {