docs: refresh mattermost group config refs

docs/channels/mattermost.md

@@ -173,10 +173,28 @@ Notes:
 
 - Default: `channels.mattermost.groupPolicy = "allowlist"` (mention-gated).
 - Allowlist senders with `channels.mattermost.groupAllowFrom` (user IDs recommended).
+- Per-channel mention overrides live under `channels.mattermost.groups.<channelId>.requireMention`
+  or `channels.mattermost.groups["*"].requireMention` for a default.
 - `@username` matching is mutable and only enabled when `channels.mattermost.dangerouslyAllowNameMatching: true`.
 - Open channels: `channels.mattermost.groupPolicy="open"` (mention-gated).
 - Runtime note: if `channels.mattermost` is completely missing, runtime falls back to `groupPolicy="allowlist"` for group checks (even if `channels.defaults.groupPolicy` is set).
 
+Example:
+
+```json5
+{
+  channels: {
+    mattermost: {
+      groupPolicy: "open",
+      groups: {
+        "*": { requireMention: true },
+        "team-channel-id": { requireMention: false },
+      },
+    },
+  },
+}
+```
+
 ## Targets for outbound delivery
 
 Use these target formats with `openclaw message send` or cron/webhooks:

docs/gateway/configuration-reference.md

@@ -452,6 +452,10 @@ Mattermost ships as a plugin: `openclaw plugins install @openclaw/mattermost`.
       dmPolicy: "pairing",
       chatmode: "oncall", // oncall | onmessage | onchar
       oncharPrefixes: [">", "!"],
+      groups: {
+        "*": { requireMention: true },
+        "team-channel-id": { requireMention: false },
+      },
       commands: {
         native: true, // opt-in
         nativeSkills: true,
@@ -481,6 +485,7 @@ When Mattermost native commands are enabled:
   Use host/domain values, not full URLs.
 - `channels.mattermost.configWrites`: allow or deny Mattermost-initiated config writes.
 - `channels.mattermost.requireMention`: require `@mention` before replying in channels.
+- `channels.mattermost.groups.<channelId>.requireMention`: per-channel mention-gating override (`"*"` for default).
 - Optional `channels.mattermost.defaultAccount` overrides default account selection when it matches a configured account id.
 
 ### Signal