Task: Diagnose billing page unavailable

Identity

Diagnose why the production /billing page for a signed-in super administrator renders the route error boundary instead of billing content.
Trace the static frontend request and render path through Go billing HTTP and PostgreSQL collection results.
Keep this task diagnostic-only; do not apply an application or deployment fix without a separate user request.

Treat the supplied screenshot as confirmed visual evidence, but do not infer the underlying exception from its generic fallback copy.
Preserve the accepted static Web + Go-only API boundary.
Do not inspect or expose authentication cookies, credentials, or Secret values.
Separate confirmed source/test evidence from live-cluster assumptions.

Confirmed the screenshot is the /billing route error boundary, which means an uncaught client render exception occurred; it is not evidence that npm run db:migrate is the cause.
Traced the super-admin path from GET /api/auth/me to GET /api/admin/billing. Normal HTTP/fetch failures are caught inside BillingManager and render an inline alert, so they do not match the screenshot.
Reproduced the browser contract failure at the Go HTTP seam: a zero-value admin overview serializes organizations, members, ledger, and priceRules as JSON null, while the frontend unconditionally calls array methods including .find, .reduce, .filter, .slice, and .map.
Confirmed the PostgreSQL adapter returns nil slices for empty result sets. This is expected on a fresh database because bootstrap creates only the super administrator; it does not create an organization, ledger entries, or price rules, and the default price catalog is seeded only from quote flow.
Confirmed the live public readiness route returns HTTP 200 with PostgreSQL configured, /billing returns the static HTML, and unauthenticated /api/admin/billing reaches Go and returns JSON HTTP 401. The authenticated live billing response body was not captured, so the exact production exception remains an evidence-backed inference rather than a directly read container/browser trace.
Removed the temporary diagnostic regression file after reproducing the failure; no application or deployment code was changed.

Temporary red-capable harness: go test ./internal/httpapi -run TestDiagnosisBillingAdminOverviewUsesJSONArraysForEmptyCollections -count=1 -v — FAIL as expected; all four collection fields were null instead of [].
Repeated the same harness with -count=3; the same four failures reproduced on all three runs in under one second.
curl.exe -sS -i --max-time 15 https://nianxxaigc.nianxx.cn/api/ready — HTTP 200, PostgreSQL configured.
Unauthenticated GET /api/admin/billing — HTTP 401 JSON 请先登录。, confirming the route reaches Go rather than Nginx static fallback.
HEAD /billing — HTTP 200 static HTML.
Independent frontend and Go read-only traces agreed on the nil-slice/null contract violation and on the route-error-versus-inline-error distinction.
Final read-only sol_reviewer: PASS for Standards and Spec; no blocker.

In a separate authorized fix task, normalize all Go billing response collections to non-nil empty slices and keep a permanent HTTP regression test asserting JSON arrays for fresh/empty state.
Add frontend response-shape validation/defaulting so malformed backend data becomes an inline actionable error instead of crashing the route subtree.
Replace the stale npm run db:migrate route-error copy; the current production architecture uses manual SQL plus Go APIs and the message obscures client contract failures.

None. This is an implementation defect within the already accepted static Web + Go API contract, not a new architecture or product decision.