fix(platform): category-scoped unread pick and channel unread counts

Filter message rows by channelId in _unreadForChannel after HyperDB find.
When every unread channel shares one category parentId, limit
_selectGuildChannelWithUnread to that category before position tie-break.

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

README.md

@@ -135,6 +135,8 @@ Primary consumer: `apps/pearcord/index.js` sidecar reading pear-pipe JSON.
 
 **v0.8.115:** `loadGuild` / `_openGuild` clears stale `activeChannelId`, then `_selectGuildChannelWithUnread` picks mention-weighted unread channels before falling back to the first text channel. `setSearch` records `searchRecentByGuild` in user prefs. View: `searchRecentQueries`.
 
+**v0.8.124:** `_unreadForChannel` filters rows by `channelId` after HyperDB find. When all unread are in one category, `_selectGuildChannelWithUnread` picks only within that `parentId`. Smoke: `test:guild-category-unread-pick`.
+
 **v0.8.123:** Equal unread/mention scores tie-break to lower `channel.position`. Smoke: `test:guild-unread-position-tie`.
 
 **v0.8.120:** `_selectGuildChannelWithUnread` scores `mentions × 1000 + unread`; mention channel beats higher plain unread. Smoke: `test:guild-mention-channel-pick`.

index.js

@@ -5059,12 +5059,25 @@ class PearcordPlatform extends EventEmitter {
       })
     }
     const mentionByCh = new Map(alertRows.map((a) => [a.channelId, a.count || 0]))
-    let best = null
-    let bestScore = -1
+    const scored = []
     for (const ch of candidates) {
       const unread = await this._unreadForChannel(ch.id, ch.guildId)
       const mentions = mentionByCh.get(ch.id) || 0
       const score = mentions * 1000 + unread
+      if (score > 0) scored.push({ ch, score })
+    }
+    let pool = scored
+    const categoryParents = new Set(
+      scored.map((r) => r.ch.parentId).filter((id) => id != null && id !== '')
+    )
+    const hasUncategorizedUnread = scored.some((r) => !r.ch.parentId)
+    if (categoryParents.size === 1 && !hasUncategorizedUnread) {
+      const parentId = [...categoryParents][0]
+      pool = scored.filter((r) => r.ch.parentId === parentId)
+    }
+    let best = null
+    let bestScore = -1
+    for (const { ch, score } of pool) {
       if (
         score > bestScore ||
         (score === bestScore && best && (ch.position || 0) < (best.position || 0))
@@ -5911,7 +5924,12 @@ class PearcordPlatform extends EventEmitter {
     })
     const since = state?.lastReadAt || 0
     const msgs = await this.db.find(COLLECTIONS.MESSAGES, { channelId })
-    return msgs.filter((m) => m.createdAt > since && m.authorId !== user.id).length
+    return msgs.filter(
+      (m) =>
+        m.channelId === channelId &&
+        m.createdAt > since &&
+        m.authorId !== user.id
+    ).length
   }
 
   async _unreadMap () {