Improve Linux terminal keymap and context menu (#16845)

Follow-up https://github.com/zed-industries/zed/pull/16085 that fixes
the search deploy to be actually a part of the terminal-related
bindings.

Part of https://github.com/zed-industries/zed/issues/16839

Also 

* fixes few other bindings to use `shift` and avoid conflicts with the
existing key bindings.
* adds terminal inline assist to the context menu and makes both the
menu and the button to dynamically adjust to `assist.enabled` settings
change

It is still unclear to me, why certain labels for certain bindings are
wrong (it's still showing `ctrl-w` for closing the terminal tab, and
`shift-insert` instead of `ctrl-shift-v` for Paste, while Insert is near
and has a `ctrl-shift-c` binding shown) but at least the keys work now.

Release notes: 
- Improved Linux terminal keymap and context menu

crates/assistant/src/prompt_library.rs

@@ -1,6 +1,4 @@
-use crate::{
-    slash_command::SlashCommandCompletionProvider, AssistantPanel, InlineAssist, InlineAssistant,
-};
+use crate::{slash_command::SlashCommandCompletionProvider, AssistantPanel, InlineAssistant};
 use anyhow::{anyhow, Result};
 use chrono::{DateTime, Utc};
 use collections::{HashMap, HashSet};
@@ -44,6 +42,7 @@ use ui::{
 use util::{ResultExt, TryFutureExt};
 use uuid::Uuid;
 use workspace::Workspace;
+use zed_actions::InlineAssist;
 
 actions!(
     prompt_library,