♻️(backend) pass the participant role in the LiveKit token

The backend previously passed an abstract is_admin_or_owner boolean
flag in the LiveKit token. That kept the frontend minimalistic and
saved it from having to handle role comparisons.

As we introduce more features that need to distinguish between the
room owner and admins, refactor the token to carry the role
directly. The frontend can then derive the relevant flags from a
richer piece of information.

src/backend/core/utils.py

@@ -66,7 +66,7 @@ def generate_token(
     username: Optional[str] = None,
     color: Optional[str] = None,
     sources: Optional[List[str]] = None,
-    is_admin_or_owner: bool = False,
+    role: Optional[str] = None,
     participant_id: Optional[str] = None,
 ) -> str:
     """Generate a LiveKit access token for a user in a specific room.
@@ -80,7 +80,7 @@ def generate_token(
                          If none, a value will be generated
         sources: (Optional[List[str]]): List of media sources the user can publish
                          If none, defaults to LIVEKIT_DEFAULT_SOURCES.
-        is_admin_or_owner (bool): Whether user has admin privileges
+        role (Optional[str]): Room's access role if any
         participant_id (Optional[str]): Stable identifier for anonymous users;
                          used as identity when user.is_anonymous.
 
@@ -88,6 +88,7 @@ def generate_token(
         str: The LiveKit JWT access token.
     """
 
+    is_admin_or_owner = role in ("owner", "administrator")
     if is_admin_or_owner:
         sources = settings.LIVEKIT_DEFAULT_SOURCES
 
@@ -128,7 +129,7 @@ def generate_token(
         .with_identity(identity)
         .with_name(display_name)
         .with_attributes(
-            {"color": color, "room_admin": "true" if is_admin_or_owner else "false"}
+            {"color": color, "room_role": role }
         )
     )
 
@@ -139,7 +140,7 @@ def generate_livekit_config(
     room_id: str,
     user,
     username: str,
-    is_admin_or_owner: bool,
+    role: Optional[str] = None,
     color: Optional[str] = None,
     configuration: Optional[dict] = None,
     participant_id: Optional[str] = None,
@@ -150,7 +151,7 @@ def generate_livekit_config(
         room_id: Room identifier
         user: User instance requesting access
         username: Display name in room
-        is_admin_or_owner (bool): Whether the user has admin/owner privileges for this room.
+        role (str): Room's access role if any
         color (Optional[str]): Optional color to associate with the participant.
         configuration (Optional[dict]): Room configuration dict that can override default settings.
         participant_id (Optional[str]): Stable identifier for anonymous users;
@@ -173,7 +174,7 @@ def generate_livekit_config(
             username=username,
             color=color,
             sources=sources,
-            is_admin_or_owner=is_admin_or_owner,
+            role=role,
             participant_id=participant_id,
         ),
     }