Webmap of published habitat: PMTiles per build #335

If done: a browser map shows link's published habitat per config, from PMTiles regenerated per build at a fixed key. If never: viewing habitat needs QGIS and a database.

The webmap from #308, "later, not the first cut".

• Build from the published rows and FWA lines cut at the measures (the same join as Desktop GeoPackage of the habitat export: segments cut from FWA at their measures #332), with tippecanoe.
• Open question: one tileset per config, or one per config × species.
• Publication and a CORS rule for browser readers are bucket-side work, outside this repo.
• Needs habitat/ public (or signed URLs) first: Gates before a floodplain item pins a habitat build: run_uid, dirty trees, versioning, public read #334.

Relates to #308.