[econ] fix challenges not persisting

apps/econ/migrations/0014_challenge_status_config.sql

@@ -0,0 +1,16 @@
+-- Store the `Config` rule tree the client posts with each weekly-challenge progress report.
+--
+-- Migration 0009 kept only the completion flag, on the grounds that the tree is the
+-- challenge's definition (static/weekly-challenge.json) and therefore identical for every
+-- player. That is only true of the tree the SERVER publishes: the client posts it back with
+-- its own progress written into the nodes — `cc` on a counter is the running count, `c`
+-- marks a satisfied node — so the posted copy is per-player state, and dropping it threw
+-- away the only record of how far along a player was. The client does the evaluating; this
+-- is where the partial progress it reports has to live between sessions.
+--
+-- Nullable, and NULL is meaningful: no report has been stored for that challenge yet (or a
+-- report arrived without a `Config`), so `/api/challenge/v2/getCurrent` serves the static
+-- tree for it unchanged. Kept in sync with CHALLENGE_STATUS_SCHEMA_DDL in
+-- src/challenge-db.ts.
+
+ALTER TABLE challenge_status ADD COLUMN config TEXT;