Second non-placeholder AWS account ID 909626172446 (CUDly host) in tracked test fixtures and docs #43

Severity: P2. Confidence: medium-high.

Follow-up to LeanerCloud/cloud-commitments-cli#1167 (HYG-02). While replacing the production account ID 540659244915, a second non-placeholder 12-digit AWS account ID was found in tracked files: 909626172446, consistently labeled "CUDly host".

Affected files (on main):

• frontend/src/__tests__/approval-details.test.ts (7 occurrences: fixtures, formatAccountLabel assertions)
• frontend/src/__tests__/settings-accounts.test.ts (2 occurrences: account fixture + aria-label selector)
• known_issues/23_ux_review_2026_04_22.md (1 occurrence: UX evidence quote)

Evidence it is likely real: it does not match any deliberate placeholder shape in .gitallowed (sequential, all-same-digit, group-block); the "CUDly host" name suggests the hosting account; and the same ID appears in an untracked local ri-helper output CSV from a real run (all-services-3y-no-upfront.csv).

Recommendation: confirm with the owner whether 909626172446 is a real account; if so, replace it with an allowlisted placeholder (e.g. 210987654321 to stay distinct from 123456789012 in two-account fixtures) in all three files, mirroring PR LeanerCloud/cloud-commitments-cli#1212. If it is synthetic, add it to .gitallowed with a comment, or preferably still swap it for a standard placeholder to keep fixtures uniform.

Kept out of PR LeanerCloud/cloud-commitments-cli#1212 because HYG-02 and issue LeanerCloud/cloud-commitments-cli#1167 scope only 540659244915 and this ID needs owner confirmation.