test(analytics): verify runtime semantics of account-filter integration tests #32

Context

golangci-lint v2 (landed in LeanerCloud/cloud-commitments-cli#1137) type-checks //go:build integration files. This exposed that the internal/analytics integration tests (postgres_analytics_db_test.go, postgres_analytics_integration_test.go) were written against a removed QueryRequest.AccountID API and the old single-string account signatures of QueryByProvider / QueryByService / QueryMonthlyTotals. They had not compiled since the account-filter model changed to AccountUUIDs + AccountExternalIDsByProvider.

A compile-fix PR restores type-checking (so CI Lint passes) by mechanically remapping the removed account arg to:

AccountExternalIDsByProvider: map[string][]string{"aws": {"<acct>"}, "gcp": {"<acct>"}}

for every query call/struct, keyed under both providers the suite uses.

What this issue tracks (NOT done in the compile-fix PR)

These integration tests run only under Docker/testcontainers (CI Lint just type-checks them), so the compile-fix did not verify their runtime behavior. The account-filter area has historically broken silently (see the global lesson: four successive "fixes" merged green while the bug survived because tests filtered the wrong column). So before trusting these tests:

• Run the suite with Docker (go test -tags=integration ./internal/analytics/) and confirm each t.Run still asserts the intended rows.
• Verify the AccountExternalIDsByProvider remap matches each test's saved snapshot providers (the blanket {"aws","gcp"} mapping may over- or under-match a block that previously filtered account-wide or by a single provider).
• Confirm the AccountUUIDs vs AccountExternalIDsByProvider choice is correct per case (snapshots are saved with an external account id, not a UUID).
• Add at least one assertion that would FAIL if the account filter matched the wrong column (regression guard for the documented trap).

Acceptance

Integration tests pass under Docker AND a deliberately-wrong account filter makes them fail (proving they actually exercise the filter).