fix(discord): strip user:/discord:/pk: prefixes in command allowFrom

Discord's formatAllowFrom now strips these prefixes before matching,
aligning with normalizeDiscordAllowList behavior used in DM admission.

Before: commands.allowFrom: ["user:123"] → no match (senderCandidates: ["123", "discord:123"])
After: commands.allowFrom: ["user:123"] → "123" → matches sender "123"

Fixes #17937

src/channels/dock.ts

@@ -219,7 +219,17 @@ const DOCKS: Record<ChatChannelId, ChannelDock> = {
           String(entry),
         );
       },
-      formatAllowFrom: ({ allowFrom }) => formatLower(allowFrom),
+      formatAllowFrom: ({ allowFrom }) =>
+        allowFrom
+          .map((entry) => String(entry).trim())
+          .filter(Boolean)
+          .map((entry) =>
+            entry
+              .replace(/^discord:/i, "")
+              .replace(/^user:/i, "")
+              .replace(/^pk:/i, "")
+              .toLowerCase(),
+          ),
     },
     groups: {
       resolveRequireMention: resolveDiscordGroupRequireMention,