chore: restructure llm plugin to be more coherent & fix various bugs in llm ui

Modules/Notifications/Sidebar/Chat/ChatContent.qml

@@ -171,7 +171,7 @@ Item {
 			Layout.alignment: ChatState.isWindow ? Qt.AlignCenter : Qt.AlignLeft | Qt.AlignVCenter
 			elide: Text.ElideRight
 			font: Tokens.font.title.medium
-			text: qsTr(root.chatData.title)
+			text: qsTr(root.chatData?.title || ChatState.title)
 		}
 	}
 
@@ -540,17 +540,17 @@ Item {
 		anchors.margins: Tokens.padding.medium
 		bg.border.color: Colors.palette.m3outlineVariant
 		bg.color: Colors.tPalette.m3surfaceContainerLowest
-		fastGlow: Chat.busy
-		glow.opacity: input.activeFocus && (!Chat.busy || ChatState.isWindow)
+		fastGlow: LlmClient.busy
+		glow.opacity: input.activeFocus && (!LlmClient.busy || ChatState.isWindow)
 		font: Tokens.font.body.small
 		implicitHeight: Math.min(root.height / 5, contentHeight + topPadding + bottomPadding)
 		focus: true
 		placeholderText: qsTr("Send a message")
 		sendIcon.font: Tokens.font.icon.medium
-		sendIcon.icon: Chat.busy ? "stop" : "arrow_upward"
+		sendIcon.icon: LlmClient.busy ? "stop" : "arrow_upward"
 		sendIcon.padding: Tokens.padding.extraSmall
-		sendIcon.opacity: text || Chat.busy ? 1.0 : 0.5
-		sendIcon.enabled: text || Chat.busy
+		sendIcon.opacity: text || LlmClient.busy ? 1.0 : 0.5
+		sendIcon.enabled: text || LlmClient.busy
 
 		Component.onCompleted: {
 			root.focusInput();
@@ -572,8 +572,8 @@ Item {
 			}
 		}
 		onButtonPressed: {
-			if (Chat.busy)
-				Chat.stop();
+			if (LlmClient.busy)
+				LlmClient.stop();
 			else
 				root.send(text);
 		}