worker: add the second origin messageweave-eu-2 to the LB origin list

BACKEND_ORIGINS_JSON now carries eu-1 and eu-2. Both are public https
origins, so the existing [vars] plaintext exception still applies and
nothing moves to secrets.

LB_VERSION stays at 2026.10.4: it is a code-version marker and the LB
logic is unchanged. The origin list is observable anyway through the
backends array in GET /healthz-worker, which now reports total 2.

Also drop a stale clause that said the origin list travels through
secret; it has lived in [vars] since aa78c13 and the same file says so
twice below it.

eu-2 needs its DNS record and a live backend before this deploy: with
LB_MAX_ATTEMPTS=2 both origins are covered, so a not-yet-deployed eu-2
costs a failed round-trip on about half the requests, and /reconcile
plus /worker run with maxAttempts=1 so those cron runs fail outright
on the half that land there first.

cloudflare-worker/wrangler.toml

@@ -12,7 +12,7 @@
 # - 真 secret 不进代码/日志（SAF-LOG-PURITY / C-NO-SECRET-IN-IMAGE；C-LB-SHARED-SECRETS：
 #   所有后端实例共享同一组 secret）。唯一明文例外是 [vars] 里的 BACKEND_ORIGINS_JSON——
 #   它的值只是公开 https origin，不是凭据（见该段的「明文例外的边界」）。
-# - 日志无密钥（SAF-LOG-PURITY）：只打「方法/路径/origin/失败类别」，origin 清单走 secret。
+# - 日志无密钥（SAF-LOG-PURITY）：只打「方法/路径/origin/失败类别」，密钥一律不进日志。
 # - 仅允许转发 safelist 路由（C-LB-SINGLE-REG-URL）；未知路径 404。
 #
 # 部署：
@@ -50,5 +50,5 @@ compatibility_flags = ["nodejs_compat_v2"]
 # 其余五个 LB_* 调参保持可调、不写死，用 dashboard 的 Add Variable 覆盖默认值即可；
 # LB_VERSION 是例外——它是版本标识，必须跟代码同版本、可 diff，写进 dashboard 反而容易漂。
 [vars]
-BACKEND_ORIGINS_JSON = '["https://messageweave-eu-1.motofans.club"]'
+BACKEND_ORIGINS_JSON = '["https://messageweave-eu-1.motofans.club","https://messageweave-eu-2.motofans.club"]'
 LB_VERSION = "2026.10.4"