docs: full sweep — update all files to v2.3.0 with self-healing system

Updated 14 files across the repo to reflect v2.3.0:
- README.md: version badge, 46 endpoints, self-healing section, changelog
- test.js: version 2.3.0
- docs/*: architecture, endpoints, index, streaming — multi-mirror + fallback
- public/*: index.html, docs.html, openapi.json, manifest.json, privacy, tos
- api/proxy.js: updated example comments
- src/routes/apiRoutes.js: endpoint count 36→46

All version refs updated from 2.1.4/2.2.0 → 2.3.0.
Endpoint count updated to 46 (added /pipe-health).
miruro.tv refs updated to multi-domain (miruro.to/ru/bz/tv).
Syntax checks pass on all JS files.

public/openapi.json

@@ -434,6 +434,12 @@
         "summary": "Health check"
       }
     },
+    "/api/pipe-health": {
+      "get": {
+        "tags": ["System"],
+        "summary": "Pipe fallback method health check"
+      }
+    },
     "/api/stats": {
       "get": {
         "tags": ["System"],