Show file open error view instead of the modal (#36764)

Closes https://github.com/zed-industries/zed/issues/36672

Before:
either 
<img width="966" height="642" alt="image"
src="https://github.com/user-attachments/assets/7263ea3c-3d48-4f4d-be9e-16b24ca6f60b"
/>
(when opening from the project panel)

or

<img width="959" height="1019" alt="image"
src="https://github.com/user-attachments/assets/834041d4-f4d6-46db-b333-803169ec4803"
/>

(for the rest of the cases)

After:

<img width="2032" height="1167" alt="Screenshot 2025-08-22 at 19 34 10"
src="https://github.com/user-attachments/assets/1aa4530b-69f6-4c3a-8ea1-d4035dbb28da"
/>

(the unified error view)

Release Notes:

- Improved unsupported file opening in Zed

---------

Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>

crates/workspace/src/invalid_buffer_view.rs

@@ -0,0 +1,111 @@
+use std::{path::PathBuf, sync::Arc};
+
+use gpui::{EventEmitter, FocusHandle, Focusable};
+use ui::{
+    App, Button, ButtonCommon, ButtonStyle, Clickable, Context, FluentBuilder, InteractiveElement,
+    KeyBinding, ParentElement, Render, SharedString, Styled as _, Window, h_flex, v_flex,
+};
+use zed_actions::workspace::OpenWithSystem;
+
+use crate::Item;
+
+/// A view to display when a certain buffer fails to open.
+pub struct InvalidBufferView {
+    /// Which path was attempted to open.
+    pub abs_path: Arc<PathBuf>,
+    /// An error message, happened when opening the buffer.
+    pub error: SharedString,
+    is_local: bool,
+    focus_handle: FocusHandle,
+}
+
+impl InvalidBufferView {
+    pub fn new(
+        abs_path: PathBuf,
+        is_local: bool,
+        e: &anyhow::Error,
+        _: &mut Window,
+        cx: &mut App,
+    ) -> Self {
+        Self {
+            is_local,
+            abs_path: Arc::new(abs_path),
+            error: format!("{e}").into(),
+            focus_handle: cx.focus_handle(),
+        }
+    }
+}
+
+impl Item for InvalidBufferView {
+    type Event = ();
+
+    fn tab_content_text(&self, mut detail: usize, _: &App) -> SharedString {
+        // Ensure we always render at least the filename.
+        detail += 1;
+
+        let path = self.abs_path.as_path();
+
+        let mut prefix = path;
+        while detail > 0 {
+            if let Some(parent) = prefix.parent() {
+                prefix = parent;
+                detail -= 1;
+            } else {
+                break;
+            }
+        }
+
+        let path = if detail > 0 {
+            path
+        } else {
+            path.strip_prefix(prefix).unwrap_or(path)
+        };
+
+        SharedString::new(path.to_string_lossy())
+    }
+}
+
+impl EventEmitter<()> for InvalidBufferView {}
+
+impl Focusable for InvalidBufferView {
+    fn focus_handle(&self, _: &App) -> FocusHandle {
+        self.focus_handle.clone()
+    }
+}
+
+impl Render for InvalidBufferView {
+    fn render(&mut self, window: &mut Window, cx: &mut Context<Self>) -> impl gpui::IntoElement {
+        let abs_path = self.abs_path.clone();
+        v_flex()
+            .size_full()
+            .track_focus(&self.focus_handle(cx))
+            .flex_none()
+            .justify_center()
+            .overflow_hidden()
+            .key_context("InvalidBuffer")
+            .child(
+                h_flex().size_full().justify_center().child(
+                    v_flex()
+                        .justify_center()
+                        .gap_2()
+                        .child("Cannot display the file contents in Zed")
+                        .when(self.is_local, |contents| {
+                            contents.child(
+                                h_flex().justify_center().child(
+                                    Button::new("open-with-system", "Open in Default App")
+                                        .on_click(move |_, _, cx| {
+                                            cx.open_with_system(&abs_path);
+                                        })
+                                        .style(ButtonStyle::Outlined)
+                                        .key_binding(KeyBinding::for_action(
+                                            &OpenWithSystem,
+                                            window,
+                                            cx,
+                                        )),
+                                ),
+                            )
+                        }),
+                ),
+            )
+    }
+}