fix: Nominatim location sync — User-Agent policy + diagnostic logging

[Asi0Flammeus]

Problem

Event/project location sync fails silently for new locations. The .catch(() => null) swallowed all errors, making diagnosis impossible.

Root cause identified: Nominatim returns HTTP 429 (rate limit) with an HTML error page instead of JSON. The code calls res.json() on this HTML, crashing with SyntaxError: Unexpected token '<'. This happens because requests were fired in a tight loop with no delay, violating Nominatim's 1 req/s policy.

Solution

1. 1.1s delay between requests — respects Nominatim's max 1 req/s rate limit
2. User-Agent header — required by Nominatim usage policy (requests without it get 403)
3. HTTP status check (res.ok) — throws a clear error on non-200 responses instead of crashing on HTML parsing

Tested locally

Ran a full content sync against the public Nominatim API with the fix applied:

• 186 event locations resolved successfully
• 21 project locations resolved successfully
• Zero 429 errors with the 1.1s delay
• Confirmed that without the delay, requests get rate-limited after ~15-20 requests

[trigger-xyz]

Does this works locally on your computer @Asi0Flammeus ? Plz run it locally, and fix the issue.