assistant2: Use cmd-n to create a new prompt editor when already in a prompt editor (#25935)

This flips the keybindings that are used to create a new thread/prompt
editor (only when you're already in a prompt editor)

Release Notes:

- N/A

assets/keymaps/default-linux.json

@@ -612,6 +612,14 @@
       "ctrl-alt-e": "assistant2::RemoveAllContext"
     }
   },
+  {
+    "context": "AssistantPanel2 && prompt_editor",
+    "use_key_equivalents": true,
+    "bindings": {
+      "cmd-n": "assistant2::NewPromptEditor",
+      "cmd-alt-t": "assistant2::NewThread"
+    }
+  },
   {
     "context": "MessageEditor > Editor",
     "bindings": {

assets/keymaps/default-macos.json

@@ -256,6 +256,14 @@
       "cmd-alt-e": "assistant2::RemoveAllContext"
     }
   },
+  {
+    "context": "AssistantPanel2 && prompt_editor",
+    "use_key_equivalents": true,
+    "bindings": {
+      "cmd-n": "assistant2::NewPromptEditor",
+      "cmd-alt-t": "assistant2::NewThread"
+    }
+  },
   {
     "context": "MessageEditor > Editor",
     "use_key_equivalents": true,

crates/assistant2/src/assistant_panel.rs

@@ -15,7 +15,8 @@ use editor::Editor;
 use fs::Fs;
 use gpui::{
     prelude::*, Action, AnyElement, App, AsyncWindowContext, Corner, Entity, EventEmitter,
-    FocusHandle, Focusable, FontWeight, Pixels, Subscription, Task, UpdateGlobal, WeakEntity,
+    FocusHandle, Focusable, FontWeight, KeyContext, Pixels, Subscription, Task, UpdateGlobal,
+    WeakEntity,
 };
 use language::LanguageRegistry;
 use language_model::{LanguageModelProviderTosView, LanguageModelRegistry};
@@ -993,12 +994,21 @@ impl AssistantPanel {
             )
             .into_any()
     }
+
+    fn key_context(&self) -> KeyContext {
+        let mut key_context = KeyContext::new_with_defaults();
+        key_context.add("AssistantPanel2");
+        if matches!(self.active_view, ActiveView::PromptEditor) {
+            key_context.add("prompt_editor");
+        }
+        key_context
+    }
 }
 
 impl Render for AssistantPanel {
     fn render(&mut self, window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
         v_flex()
-            .key_context("AssistantPanel2")
+            .key_context(self.key_context())
             .justify_between()
             .size_full()
             .on_action(cx.listener(Self::cancel))