fix terminal keyboard shortcut error when adding content to context (#5161)

## Fix terminal keyboard shortcut error when adding content to context

**Fixes:** [#2276](https://github.com/RooCodeInc/Roo-Code/issues/2276)

**Problem:**
- Using keyboard shortcuts to add terminal content to context threw error: "Cannot read properties of undefined (reading 'selection')"
- Context menu worked correctly, but keyboard shortcuts failed

**Root Cause:**
- Command handler accessed `args.selection` without null checking
- When triggered via keyboard shortcut, VS Code passes `undefined` for `args` parameter
- When triggered via context menu, VS Code passes an object with `selection` property

**Solution:**
- Changed `args.selection` to `args?.selection` using optional chaining
- Maintains existing fallback behavior when no selection is available
- Preserves backward compatibility with context menu functionality

**Files Modified:**
- `src/activate/registerTerminalActions.ts` - Added null safety for args parameter

**Testing:**
- ✅ Keyboard shortcuts now work without errors
- ✅ Context menu functionality preserved
- ✅ Fallback to `Terminal.getTerminalContents()` works in both scenarios

src/activate/registerTerminalActions.ts

@@ -20,7 +20,7 @@ const registerTerminalAction = (
 ) => {
 	context.subscriptions.push(
 		vscode.commands.registerCommand(getTerminalCommand(command), async (args: any) => {
-			let content = args.selection
+			let content = args?.selection
 
 			if (!content || content === "") {
 				content = await Terminal.getTerminalContents(promptType === "TERMINAL_ADD_TO_CONTEXT" ? -1 : 1)