fix: suppress stale walk-or-drive advice and show CBP report clocks

[sbc1-code]

Summary

• Retain the actual snapshot retrieval timestamp and suppress all walk/drive/tie verdicts and recommendation badges for stale, missing, invalid or future clocks.
• Re-evaluate age each minute; reuse existing 45/90-minute freshness thresholds without changing feed/fallback semantics.
• Show retrieval freshness separately from raw CBP lane clocks, including unavailable clocks; replace unconditional live/current wording in runtime and prerender metadata.
• Extend EN/ES desktop/mobile regression coverage for retained zero waits, aging into stale without a feed, failed refresh, recovery, future timestamps, raw report clocks and existing closure/pending/Back behavior.
• No changes to route inventory, cameras, data feeds, ads, dependencies or thresholds.

Verification

• PASS: 112 unit tests across existing npm test suites.
• PASS: full build + prerender; static FAQ/hreflang checks; dependency audit (0 high/critical); JS/CSS bundle budgets; git diff --check and new-module syntax checks.
• Typecheck: existing errors, with exactly the same 224 diagnostic lines as a clean main checkout after normalizing shifted source line numbers. No added diagnostics.
• Lint unavailable: ESLint and configured plugins are not installed/declared in repository dependencies; no dependency changes made.
• BLOCKED locally: browser release suite cannot launch Chromium because process_singleton_posix.cc socket() returns Operation not permitted, including an elevated retry. Browser tests are not claimed as passed. Existing Verify BorderPulse CI runs the full build and npm test on this branch/PR; its exact-head browser result is required before merging.
• Independent review requested. Addressed preliminary review findings: dark-mode contrast for new small labels and deterministic failed-refresh completion rather than a fixed sleep.

Release verification after approval

1. Require green exact-head Verify BorderPulse browser checks, independent review and normal production publication.
2. Check deployed walk-or-drive assets/metadata match the approved commit.
3. With external/ad requests blocked, verify EN/ES desktop/mobile fresh, stale/future, offline retention/recovery and separate raw lane-clock labels; preserve closure/pending and Back behavior.
4. Inspect the actual live fetched_at separately from per-lane report clocks. Do not interpret a healthy live API as an outage merely because static fallback is older.

Draft intentionally remains unmerged pending browser gate and independent review.