config: give mainnet the two public archive nodes as fallbacks

Mainnet was the only chain left on a single endpoint, and that endpoint is our
own node — so a restart on bob took the flagship chain off the site while both
testnets, on two endpoints each, stayed up.

Our node stays first, and has to: loopback pays no network hop, and `127.0.0.1/32`
is the only address whitelisted against its `--rpc-rate-limit 300`. Behind it are
`rpc1-` and `rpc2-mainnet.quantus.com`, both of which answer `archive_v1_*`,
report the same genesis and the same runtime, and accept a `wss://` upgrade.

They took some finding, which is recorded in the template's comment so the next
person does not repeat the search: mainnet uses a different domain *and* a
different prefix from the testnets, its bootnodes serve only p2p on 30333, and
the official explorer talks to a GraphQL indexer rather than to any node at all.

This buys availability, not depth. Failover moves on a transport failure, and a
pruned node answers `{"result": null}` — a success, so a deep state read would
stop at it rather than fall through to a peer that has the answer. Filed as #9.

Closes #8

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Jp6a8EDar9ueEhAxzep4V5

asset/config/config.toml.tmpl

@@ -92,8 +92,32 @@ mainnet = true
 # stays in the site's navigation; it is simply no longer navigable, because
 # authorship comes from headers and we no longer hold an endpoint that serves
 # them. That is the ordinary `no_endpoint` state, not an outage.
-rpc_url = "http://127.0.0.1:9944"
-ws_url = "ws://127.0.0.1:9944"
+# Our own node first, and it must stay first: loopback pays no network hop, and
+# `127.0.0.1/32` is the only address whitelisted against the node's own
+# `--rpc-rate-limit 300`. Reaching it by its mesh name instead would cap the
+# backfill at a hundred blocks a minute for no reason.
+#
+# The two public archive nodes behind it are the fallback. They were not easy to
+# find: mainnet uses a different domain *and* a different prefix from the
+# testnets — `rpc1-mainnet.quantus.com`, where Planck has
+# `a1-planck.quantus.cat` — and its bootnodes (`a1..a7-p2p-mainnet.quantus.com`)
+# expose only port 30333, so they gossip and serve nothing. The official
+# explorer is no help either: it talks to a GraphQL indexer rather than to a
+# node.
+#
+# This buys availability, not depth. Failover moves on a transport failure, and
+# a node that has pruned answers `{"result": null}` — a success, so a deep read
+# stops at it rather than falling through to a peer that holds the state. #9.
+rpc_urls = [
+    "http://127.0.0.1:9944",
+    "https://rpc1-mainnet.quantus.com",
+    "https://rpc2-mainnet.quantus.com",
+]
+ws_urls = [
+    "ws://127.0.0.1:9944",
+    "wss://rpc1-mainnet.quantus.com",
+    "wss://rpc2-mainnet.quantus.com",
+]
 # TWELVE, not the 6.0 Planck used. `TARGET_BLOCK_TIME_MS` is 12_000 in the
 # runtime bob actually runs — verified at commit b017e642, which is the
 # `0.11.1-b017e6420aa` its `system_version` reports, not merely at the tip of