Canonicalize reward IDs during case-insensitive mapping

docs/export-format.md

@@ -84,6 +84,12 @@ Current stable pool IDs:
 Avoid using `banner.name`, `reward_name`, `reward_type` or `reward_rank` as primary IDs. They
 are useful display fields, but may change when mapping files are updated.
 
+Known `reward_id` values are matched case-insensitively and emitted using the
+canonical casing from the bundled mapping. This prevents packet/asset casing
+differences from dropping display metadata or producing different downstream
+IDs. An unknown reward keeps the casing decoded from the packet. Reward IDs are
+not UID inputs, so canonicalizing their casing does not change pull UIDs.
+
 ## Stability notes
 
 Every JSON record is exported with a stable `uid`. Re-scanning deeper history can

docs/packet-format.md

@@ -101,6 +101,8 @@ Decoded fields:
   Arc/Gashapon history uses the same scheme at `ASCII * 2`.
 - The decoder decodes the key to its id string and looks up display metadata
   in `mappings/arcs.json`, `mappings/characters.json`, and `mappings/items.json`.
+  Lookups are case-insensitive across Monopoly, Arc, and Mystery Box decoders;
+  known IDs are emitted using mapping-canonical casing.
   Achievement display metadata is generated separately in
   `mappings/achievements.json`.
   Unknown rewards still export their decoded id with empty name/rank.