WSA Implementation

[mudhoney]

Adds WSA ingestion, a native-HPC coordinate snapshot on every event, and a canonical
footprint shape — plus the tooling to purge and re-collect a single source.

WSA

• Collects coronal-hole boundaries and magnetic-connectivity footpoints from the CCMC WSA
  dashboard.
• Registered as source_id 3 and collected by createStandard, chunked one day at a time like
  HEK.
• Coronal holes are grouped per forecast window, so one event carries all of that window's
  contours.
• Uses its own HTTP client because CCMC answers 403 to the default user agent.

Coordinates

• Every event now stores a native-HPC snapshot (x_hpc, y_hpc, footprint_hpc) in arcsec at
  its own coordinate_time.
• Snapshot resolution moved out of the rotator into HPCResolver, with one strategy per
  coordinate system.
• Coordinator failover split into FailoverCoordinator, leaving CoordinateRotator to rotate
  only.
• Added Carrington→helioprojective batch conversion, since WSA footprints are stored in
  degrees and must transform per vertex.
• The coordinator client now throws if it returns a different number of coordinates than
  were sent.
• make backfill-hpc fills the snapshot on existing rows, resumable and chunked.
• Raised the HTTP client timeout to 180s for slow HEK transfers.

Footprints — breaking

• footprint is now always a list of polygons [[{x,y},…],…], for every source including
  single-polygon ones.
• Existing rows are converted by the wrap_footprints_in_polygon_list migration.

API

• frames_with_selections serves the arcsec snapshot as the base and rotates centers only, so
  one delta is valid for every coordinate system.
• Added ?withDelta to that endpoint for dx/dy offsets instead of absolute coordinates.
• POST /helioviewer/events/from/{from}/to/{to} accepts path>>uuid selectors to pick a single
  event by id.
• Removed POST /helioviewer/events/{sources}/observations, superseded by
  frames_with_selections.
• WSA events no longer report event_type: UNK on the timeline and now carry their API URLs
  in views.
• WSA is included in the stats endpoint.

Tooling

• make purge-path PATHS=… deletes an event path and everything attached to it: sidecars,
  rows, region links, distribution buckets, orphaned regions and failure records.
• make collect SOURCES="A,B" restricts a run to named sources, and make sources lists every
  source with the path it writes to.
• The collect log marks each registered source [FETCH] or [SKIP], so a filter's effect is
  visible before the run starts.
• make reset is now a dry run reporting what it would drop, unless APPLY=1.
• The RHESSI seeder maintains distribution buckets, which it previously ignored entirely.
• storage/ is gitignored to keep git responsive.

Breaking changes

• footprint shape. Consumers iterating points directly will now get arrays; they must handle
  the nested shape before this merges.
• Removed endpoint. Anything still calling POST /helioviewer/events/{sources}/observations
  gets a 404.

Deploy

• Two migrations run: add_hpc_fields_to_events_table and wrap_footprints_in_polygon_list.
• Stop the scheduler before migrating — a collection racing the migration writes the old
  footprint shape back.
• Roll back by restoring the backup, not migrate-rollback: down() cannot unwrap
  multi-polygon footprints, and WSA coronal holes have many.
• WSA now runs in every scheduled collection, adding roughly 3 minutes to each 6-minute
  cycle and new sustained load on CCMC.
• Run make backfill-hpc APPLY=1 afterwards; until it completes, endpoints fall back to
  stored values.