Explorer + Snap: nginx /snap 200, runbook, apply-nginx script, verify docs

Co-authored-by: Cursor <cursoragent@cursor.com>

docs/EXPLORER_API_ACCESS.md

@@ -2,6 +2,8 @@
 
 The frontend is reachable at **https://explorer.d-bis.org** (FQDN) or by **VM IP** (**http://192.168.11.140**). In both cases it needs the **Blockscout v2 API** at the same origin under `/api/`. If you see **502 Bad Gateway**, **no blocks/transactions feeds**, or "Failed to load", the API may be unreachable. Use this checklist to verify and restore access.
 
+**See also:** [EXPLORER_API_REFERENCE.md](EXPLORER_API_REFERENCE.md) for the list of Blockscout v2 endpoints used by the frontend.
+
 ---
 
 ## No feeds (blocks/transactions empty or stuck on “Loading…”)
@@ -217,15 +219,25 @@ if ($request_method = OPTIONS) {
 From the repo (Proxmox host or inside VMID 5000):
 
 ```bash
-cd /home/intlc/projects/proxmox/explorer-monorepo
-bash scripts/verify-explorer-api-access.sh
+cd /path/to/explorer-monorepo
+bash scripts/verify-explorer-api-access.sh [BASE_URL]
 ```
 
 The script checks:
 
 - Blockscout (or API) responding on port 4000 (when run inside the VM).
-- Nginx serving `/api/` (local and, if BASE_URL set, public URL).
-- HTTP 200 on `/api/v2/stats` and optionally `/api/v2/blocks`.
+- Nginx serving `/api/` and having `location /snap/` (when run inside the VM or with `pct`).
+- HTTP 200 on `/api/v2/stats`, `/api/v2/blocks`, `/api/v2/transactions`.
+- Explorer frontend at `/` returns 200.
+- Chain 138 Snap companion site at `/snap/` returns 200 or 301 and contains expected content when 200.
+
+**Full verification (single place for all checks — API, explorer, Snap):**
+
+```bash
+bash scripts/verify-vmid5000-all.sh [BASE_URL]
+```
+
+Run this after every deploy or nginx change to confirm explorer and Snap site are reachable and correct.
 
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