🧾 docs: Document the Composer Footer Placement and messageAuthor

content/docs/configuration/librechat_yaml/object_structure/interface.mdx

@@ -55,6 +55,7 @@ These are fields under `interface`:
 - `marketplace`
 - `landingHeading`
 - `landingFooter`
+- `messageAuthor`
 - `runningChatRename`
 - `historyCacheTtlMs`
 - `historyCacheRecent`
@@ -1810,13 +1811,24 @@ interface:
 
 ## landingFooter
 
-Shows the generic disclaimer and policy links beneath the welcome screen's composer. A configured custom footer still renders when this is `false`.
+Shows the generic disclaimer and policy links on the welcome screen: at the bottom of the page (`true`), directly under the composer (`composer`), or not at all (`false`). A configured custom footer still renders when this is `false`.
 
 **Default:** `true`
 
 ```yaml filename="interface / landingFooter"
 interface:
-  landingFooter: false
+  landingFooter: composer
+```
+
+## messageAuthor
+
+Chooses which responses show the author's avatar and name above their content: all of them (`always`), or only those from an agent other than the one the header's model selector shows (`whenDifferent`). With `whenDifferent`, the selected agent's responses start directly with their content, and screen readers still announce the author. Responses keep their author when no selector is shown, such as with `modelSelect: false` and no model specs, and in read-only subagent threads.
+
+**Default:** `always`
+
+```yaml filename="interface / messageAuthor"
+interface:
+  messageAuthor: whenDifferent
 ```
 
 ## runningChatRename