fix: change "Add to Context" keybinding to avoid Redo conflict

Fixes #8652

Changed the keyboard shortcut for "Add to Context" from Ctrl+Y/Cmd+Y
to Ctrl+K Ctrl+A (Cmd+K Cmd+A on Mac) to avoid conflicting with the
standard Redo operation in VS Code.

Author: roomote

src/package.json

@@ -310,10 +310,10 @@
 		"keybindings": [
 			{
 				"command": "roo-cline.addToContext",
-				"key": "cmd+y",
-				"mac": "cmd+y",
-				"win": "ctrl+y",
-				"linux": "ctrl+y",
+				"key": "cmd+k cmd+a",
+				"mac": "cmd+k cmd+a",
+				"win": "ctrl+k ctrl+a",
+				"linux": "ctrl+k ctrl+a",
 				"when": "editorTextFocus && editorHasSelection"
 			},
 			{