fix(aviation): replace broken lock with direct cache + cancellation tiers

[koala73]

Summary

• Root cause: Redis SETNX lock waited 3s but AviationStack takes ~25s for 50 airports → every lock-loser fell back to simulation → real API data was never served
• Fix: Replace fetchIntlWithLock/tryAcquireLock with direct getCachedJson/setCachedJson and conditional TTL (30min real, 5min simulation)
• Cancellation tiers: DXB at 32% cancelled was silently dropped (null). Added ≥20% → moderate, ≥10% → minor thresholds
• NOTAM defense: ICAO CloudFront returns HTML challenge pages from Vercel IPs — added content-type check before JSON parse

Verified with live API

AUH: 100 flights, 92 cancelled → severe closure ✓
DXB: 100 flights, 32 cancelled → moderate ✓ (was null before)
DOH: 100 flights, 2 cancelled  → no alert ✓ (correct)
NOTAM: returns valid JSON locally, HTML from Vercel IPs (handled gracefully)

Test plan

• npx tsc --noEmit passes
• Deploy → check Vercel logs for [Aviation] AviationStack OK: instead of falling back to simulation
• AUH should show severe closure alert in aviation panel
• DXB should show moderate delay (32% cancelled) instead of simulated data
• NOTAM errors should log clean warning, not JSON parse crash

Supersedes #589

[chatgpt-codex-connector]

You have reached your Codex usage limits for code reviews. You can see your limits in the Codex usage dashboard.

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
worldmonitor	Building	Preview, Comment	Feb 28, 2026 8:38pm
worldmonitor-finance	Building	Preview, Comment	Feb 28, 2026 8:38pm
worldmonitor-happy	Building	Preview, Comment	Feb 28, 2026 8:38pm
worldmonitor-startup	Building	Preview, Comment	Feb 28, 2026 8:38pm