Production promotion — prod-20260818-132909

What's Changed

• fix(sdk): never authorize an x402 payment that already settled (#1521) by @claude[bot] in #1527
• fix(build): mcp-server is a private workspace consumer, not a published one (#1526) by @claude[bot] in #1528
• feat(qa): preflight the resources a money-flow run consumes (#1530) by @claude[bot] in #1532
• test(qa): drop the legacy-rail x402 legs — x402 coverage is delegation-rail only by @d-hinders in #1535
• fix(qa): give every purchasing leg a per-attempt idempotency key (#1534) by @claude[bot] in #1536
• fix(relayer): one nonce view per chain — delete the duplicate provider pair (#1533) by @claude[bot] in #1537
• chore(release): bump all published packages to 0.1.26-alpha.0 by @claude[bot] in #1539
• promote: dev → main (QA reliability chain + #1521 SDK fix + 0.1.26-alpha.0) by @claude[bot] in #1540

Full Changelog: prod-20260817-193022...prod-20260818-132909