Panic on `/terminal` if Assistant has been dragged out of dock

[notpeter]

Summary

Reproducible Panic if you type /terminal in Assistant1 once it's been undocked.

Steps to trigger the problem:

1. Open an assistant panel
2. Drag the "New Chat" tab to the middle/editor pane.
3. Type /terminal and press enter.

Actual Behavior: Panic! at the disco

Expected Behavior: don't panic

Zed Version and System Specs

Zed: v0.181.0 (Zed Nightly 7e4320f)
OS: macOS 15.3.2
Memory: 64 GiB
Architecture: aarch64

If applicable, attach your ~/Library/Logs/Zed/Zed.log file to this issue.

{
  "thread": "main",
  "payload": "cannot read assistant_context_editor::context_editor::ContextEditor while it is already being updated",
  "location_data": {
    "file": "/Users/administrator/actions-runner/_work/zed/zed/crates/gpui/src/app/entity_map.rs",
    "line": 139
  },
  "backtrace": [
    "backtrace::capture::Backtrace::create::h52f9271ec334a762+13385456",
    "backtrace::capture::Backtrace::new::hce8e52c9de3d5882+13385264",
    "zed::reliability::init_panic_hook::{{closure}}::h44d1c76342e5b0bf+96274416",
    "std::panicking::rust_panic_with_hook::hc9e2ec2a12b10e12+76129788",
    "std::panicking::begin_panic_handler::{{closure}}::h3b6449e2eb83bf4c+76128616",
    "std::sys::backtrace::__rust_end_short_backtrace::h38d85099ddd107a3+76122984",
    "_rust_begin_unwind+76127788",
    "core::panicking::panic_fmt::hd4003258f6ab7b29+105792448",
    "gpui::app::entity_map::double_lease_panic::h69d54bfa771bcc55+1203680",
    "<gpui::app::entity_map::Entity<T> as workspace::item::ItemHandle>::act_as_type::h99446228eb397d94+2106948",
    "<assistant_slash_commands::terminal_command::TerminalSlashCommand as assistant_slash_command::SlashCommand>::run::hb5f37c6136eb6eb5+9911540",
    "assistant_context_editor::context_editor::ContextEditor::run_command::hb6ff1de595544e66+8228984",
    "assistant_context_editor::slash_command::SlashCommandCompletionProvider::complete_command_name::{{closure}}::{{closure}}::{{closure}}::{{closure}}::{{closure}}::{{closure}}::h09c4d2160bfcf24a+8517980",
    "editor::Editor::do_completion::h0e80bc3b2ae9522c+29277948",
    "editor::element::register_action::{{closure}}::he64232ac7d8d3414+28476140",
    "gpui::window::Window::dispatch_action_on_node::h1028865f684712ec+40691600",
    "gpui::window::Window::dispatch_event::h38363d97b7ec6954+40753604",
    "gpui::window::Window::new::{{closure}}::hf21f645428f86131+40634924",
    "gpui::platform::mac::window::handle_key_event::hd8b9bc39b5a1bdcb+40451484",
    "<gpui::platform::mac::platform::MacPlatform as gpui::platform::Platform>::run::hf175604a325e58b2+40380348",
    "gpui::app::Application::run::h10d8f80177ae39b3+94153252",
    "zed::main::hb8cef8b601c7c1fc+96297632",
    "std::sys::backtrace::__rust_begin_short_backtrace::h750b8f5b79cb41c4+96136488",
    "std::rt::lang_start::{{closure}}::h698c5cfaedcebc0e+96729192",
    "std::rt::lang_start_internal::h5f91760815528aa2+76065024",
    "_main+96311704"
  ],
  "app_version": "0.181.0",
  "app_commit_sha": "7e4320f587bf36fcba8e9f7858ad9172e7e8f702",
  "release_channel": "nightly",
  "target": "aarch64-apple-darwin",
  "os_name": "macOS",
  "os_version": "15.3.2",
  "architecture": "aarch64",
  "panicked_on": 1743016343405,
  "system_id": "e6b5b705-51bf-4704-80d7-4964627c0c04",
  "installation_id": "9146990d-7463-4795-bdf0-9357bd824f4b",
  "session_id": "2aaf9c02-be82-4b39-9307-f3580ed35228"
}

[notpeter]

You can't do this anymore. Closing.