Wires the traefik stack to read two new fields from secret/viktor:
* x402_wallet_address -> 0xCc33BD250d39752e0ceaB616f8a05F72274a659f
* alertmanager_slack_api_url (existing) -> reused as the per-payment
notification webhook so payment events arrive in the same Slack
channel as other infra alerts.
Gateway now runs `wallet_set:true, dry_run:false`. Verified end-to-end:
- Browser UA on all 9 sites -> 200 (passes through to Anubis)
- python-requests/2.31 + scrapy + ClaudeBot UA -> 402 with
PaymentRequiredResponse, payTo == Viktor's wallet, amount=10000
micro-USDC, network=base, asset=Base USDC contract
- Direct Slack-webhook test from inside cluster -> HTTP 200
Image bumped to forgejo.../x402-gateway:d9b83125 with Slack-format
notification payload (text=..., username=x402-gateway,
icon_emoji=💰; auxiliary fields preserved for richer receivers).
Notifications fire on every successful X-PAYMENT validation; failures
on Slack webhook are logged at WARN, never block the request, never
double-charge the bot.
Viktor
c36858eddd