feat(db): userPrefsMirror schema for pinned DM ids v0.8.635

Add HyperDB user-prefs-mirror collection so pinned DM channel ids can
materialize on disk with JsonStore fallback when schema rebuild is blocked.

Co-authored-by: Cursor <[email protected]>

build.js

@@ -277,6 +277,16 @@ ns.register({
   ]
 })
 
+ns.register({
+  name: 'userPrefsMirror',
+  compact: true,
+  fields: [
+    { name: 'userId', type: 'string', required: true },
+    { name: 'pinnedDmChannelIdsJson', type: 'string' },
+    { name: 'updatedAt', type: 'uint', required: true }
+  ]
+})
+
 Hyperschema.toDisk(schema)
 
 const db = HyperDB.from(SCHEMA_DIR, DB_DIR)
@@ -367,6 +377,11 @@ pdb.collections.register({
   schema: '@pearcord/dmChannelMeta',
   key: ['channelId']
 })
+pdb.collections.register({
+  name: 'user-prefs-mirror',
+  schema: '@pearcord/userPrefsMirror',
+  key: ['userId']
+})
 
 pdb.indexes.register({
   name: 'messages-by-channel-time',