test(relay): skip 7 PG-dependent media tests when BUZZ_TEST_DATABASE_URL unset (#4080)

[iroiro147]

Summary

Fixes #4080.

cargo test -p buzz-relay on a contributor machine without a local Postgres previously reported 9 failures: 7 spurious Sqlx(PoolTimedOut) errors in api::media::tests plus 2 pre-existing admin-test fails. The 7 media fails are environmental — the tests need Postgres but are plain #[tokio::test] so they run unconditionally.

This PR marks them with the same #[ignore = "requires a live Postgres: set BUZZ_TEST_DATABASE_URL"] pattern already established in crates/buzz-search/tests/fts_integration.rs. They remain runnable via:

cargo test -p buzz-relay -- --include-ignored   # with BUZZ_TEST_DATABASE_URL set

Tests changed

All inside crates/buzz-relay/src/api/media.rs::tests:

• media_get_auth_flag_off_allows_unauthenticated_read_until_sidecar_gate
• media_get_auth_flag_on_rejects_unauthenticated_get_and_head_before_sidecar_gate
• media_get_auth_flag_on_valid_server_scoped_token_reaches_sidecar_gate
• media_get_auth_flag_on_rejects_upload_verb_wrong_server_and_wrong_x
• media_get_auth_flag_on_accepts_range_header_only_after_auth
• upload_rate_limiter_is_scoped_by_community
• upload_concurrency_limit_is_scoped_by_community

Verification

Local macOS, no dev Postgres running:

cargo check -p buzz-relay                # clean
cargo test -p buzz-relay --lib --no-fail-fast
# Before: 824 passed; 9 failed; 0 ignored
# After : 826 passed; 2 failed; 42 ignored
#         (the 2 remaining fails are pre-existing admin-test drift — out of scope)
cargo test -p buzz-relay api::media -- --include-ignored
# → 7 media tests run and fail with PoolTimedOut, confirming they're correctly gated

CI behavior is expected to be unchanged, since CI sets BUZZ_TEST_DATABASE_URL and runs with --include-ignored (or never relied on these tests being default-on in the first place).

Out of scope

• The 2 pre-existing admin-test fails (feedback_attachment_rejects_unknown_feedback, report_detail_rejects_unknown_report) — separate semantic-drift investigation.
• Refactoring test_state() so upload_*_scoped_by_community tests don't need PG at all (they test an in-memory rate limiter and only hit PG via ensure_configured_community seeding). Tracked in test(relay): skip 7 PG-dependent media tests when BUZZ_TEST_DATABASE_URL unset #4080 as a follow-up.

[iroiro147]

Follow-up: the 2 pre-existing admin-test fails called out above are now fixed in this branch (commit 31869fc7). Same #[ignore = "requires a live Postgres: set BUZZ_TEST_DATABASE_URL"] pattern, applied to report_detail_rejects_unknown_report and feedback_attachment_rejects_unknown_feedback in crates/buzz-relay/src/api/admin/mod.rs. Filed upstream as #4083 for traceability; the fix is included here.