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.
• Coronal holes are fetched with a single fixed satellite (SWPC_REALTIME). CCMC confirmed the maps are identical whatever sat is passed, so the per-satellite loop is gone: 78 requests/day → 13.
• The tree is WSA>>Coronal Hole>>AGONG and >>GONGZ with no satellite level; the 12 AGONG ensemble members sit under the one node, labeled Real 0…11. Magnetic connectivity stays per-satellite (WSA>>Magnetic Connectivity>>{sat}>>AGONG), since footpoints genuinely differ per spacecraft.

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.
• x_hpc/y_hpc/footprint_hpc are internal and never serialized. They're the rotator's input; emitting them duplicated every vertex in the response and exhausted the 128 MB limit on the WSA observation endpoint.
• 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.
• Each timestamp in frames_with_selections carries dx/dy arcsec offsets from the snapshot base; the client renders pin = center + (dx, dy) and shifts every footprint vertex by the same delta.
• 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.
• An unknown SOURCES name now fails the run up front and prints the valid list (make sources), instead of silently collecting nothing.

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: wrap_footprints_in_polygon_list and add_hpc_fields_to_events_table.
• 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.
• Run make backfill-hpc APPLY=1 afterwards; until it completes, endpoints fall back to
  stored values.
• WSA now runs in every scheduled collection: 19 upstream requests per day-chunk (13 coronal-hole + 6 footpoint), paced 1–3 s apart.

Known Limitations

• Far-side clipping is not handled: every WSA vertex is projected whether or not it faces the observer, so far-side coronal-hole contours land on the disk. Fix pending.
• Rotation assumes observer=earth for every vantage point; footpoints for PSP, SO, MARS and STEREOA are approximated.
• Coronal-hole contours can nest (an island inside a hole). CCMC's WSA developer confirmed this is their contouring's behaviour and not to be corrected.
• Selecting the AGONG node draws all 12 realizations at once, by design.