fix(map): /api/tiles SMP prefetch vs OSMF tile policy — User-Agent contact info and offline-packaging eligibility

Found during the #376 spec review (pre-existing, not caused by it).

Problem

1. functions/api/tiles/index.ts:240 sends User-Agent: comapeo-cloud-app/1.0 (tile-proxy) — the OSMF tile usage policy requires a clear, unique User-Agent naming the app with sufficient contact info. Current UA has no contact point.
2. src/lib/map/smp-download.ts (~:145-152) prefetches tile.openstreetmap.org tiles through /api/tiles for offline packaging. OSMF defines bulk downloading as pre-emptive fetching of tiles other than those the user is actively viewing and names offline archives — SMP downloads of OSM-based basemaps fall under this.

Scope

• Decide with maintainers: exclude OSM Standard (and OSMF-hosted) entries from SMP offline packaging, or seek an OSMF exception/partner tile source for offline use.
• Add contact info to the proxy User-Agent (needs a maintainable contact value — not hardcoded personal email in an OSS repo; consider a project alias).
• Document the outcome in the tile-proxy docs.

References

• OSMF tile usage policy (bulk download + UA requirements)
• Wikimedia-style third-party prohibitions do not apply to OSM tiles generally, but the bulk-download clause does.

Related: #376 (spec §Non-goals; its docs/qa/376.md must reference this issue as a known limitation).

Read the OSMF tile usage policy, then inspect functions/api/tiles/index.ts around line 240 and src/lib/map/smp-download.ts around lines 145-152. Confirm the maintainers’ choice for OSM-hosted offline packaging and the project contact value, then update the tile-proxy docs and docs/qa/376.md; done means the policy outcome, User-Agent contact, and known limitation are documented and implemented.