Fetch schema:version from OvertureMaps/schema tags

Type

Task

Scope

Multi-theme or Platform

Skillset

engineering

Description

Context

reconcile passes "" as the schema arg to build_single_release, so every catalog it produces ships schema:version: null (visible on prod today for 2026-08-19.0 at every level). Same bug in Python main — inherited, not a Rust regression. We plan to pair schema tags with release tags in OvertureMaps/schema — e.g. v1.18.0 and 2026-10-15.0 on the same commit — giving a queryable release→schema mapping.

Proposed change

Add fetch_schema_from_github(release_id) -> Result<Option<String>> in src/storage/http.rs:

• Query https://api.github.com/repos/OvertureMaps/schema/tags; find the tag whose commit also carries a release_id-shaped tag; return the paired v* tag stripped of the leading v. Return None if no pair found.
• Cache the tag set in-memory for the run so reconcile only hits the API once.

Wire the resolver into apply_diff in reconcile.rs — the build_single_release(..., release, "", ...) call.

Fail-open: None from the resolver → keep passing "" (today's behavior). Network errors log and continue. A follow-up will add parquet-metadata as the primary source once Oct+ releases stamp it, demoting GH lookup to fallback.