component: Add component and component_preview crates to power UI components (#24456)

This PR formalizes design components with the Component and
ComponentPreview traits.

You can open the preview UI with `workspace: open component preview`.

Component previews no longer need to return `Self` allowing for more
complex previews, and previews of components like `ui::Tooltip` that
supplement other components rather than are rendered by default.

`cargo-machete` incorrectly identifies `linkme` as an unused dep on
crates that have components deriving `IntoComponent`, so you may need to
add this to that crate's `Cargo.toml`:

```toml
# cargo-machete doesn't understand that linkme is used in the component macro
[package.metadata.cargo-machete]
ignored = ["linkme"]
```

Release Notes:

- N/A

---------

Co-authored-by: Marshall Bowers <git@maxdeviant.com>

crates/workspace/Cargo.toml

@@ -34,6 +34,7 @@ call.workspace = true
 client.workspace = true
 clock.workspace = true
 collections.workspace = true
+component.workspace = true
 db.workspace = true
 derive_more.workspace = true
 fs.workspace = true

crates/workspace/src/theme_preview.rs

@@ -27,7 +27,6 @@ pub fn init(cx: &mut App) {
 enum ThemePreviewPage {
     Overview,
     Typography,
-    Components,
 }
 
 impl ThemePreviewPage {
@@ -35,7 +34,6 @@ impl ThemePreviewPage {
         match self {
             Self::Overview => "Overview",
             Self::Typography => "Typography",
-            Self::Components => "Components",
         }
     }
 }
@@ -64,9 +62,6 @@ impl ThemePreview {
             ThemePreviewPage::Typography => {
                 self.render_typography_page(window, cx).into_any_element()
             }
-            ThemePreviewPage::Components => {
-                self.render_components_page(window, cx).into_any_element()
-            }
         }
     }
 }
@@ -392,28 +387,6 @@ impl ThemePreview {
             )
     }
 
-    fn render_components_page(&self, window: &mut Window, cx: &mut App) -> impl IntoElement {
-        let layer = ElevationIndex::Surface;
-
-        v_flex()
-            .id("theme-preview-components")
-            .overflow_scroll()
-            .size_full()
-            .gap_2()
-            .child(Button::render_component_previews(window, cx))
-            .child(Checkbox::render_component_previews(window, cx))
-            .child(CheckboxWithLabel::render_component_previews(window, cx))
-            .child(ContentGroup::render_component_previews(window, cx))
-            .child(DecoratedIcon::render_component_previews(window, cx))
-            .child(Facepile::render_component_previews(window, cx))
-            .child(Icon::render_component_previews(window, cx))
-            .child(IconDecoration::render_component_previews(window, cx))
-            .child(KeybindingHint::render_component_previews(window, cx))
-            .child(Indicator::render_component_previews(window, cx))
-            .child(Switch::render_component_previews(window, cx))
-            .child(Table::render_component_previews(window, cx))
-    }
-
     fn render_page_nav(&self, window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
         h_flex()
             .id("theme-preview-nav")

crates/workspace/src/workspace.rs

@@ -148,6 +148,7 @@ actions!(
         Open,
         OpenFiles,
         OpenInTerminal,
+        OpenComponentPreview,
         ReloadActiveItem,
         SaveAs,
         SaveWithoutFormat,
@@ -378,6 +379,7 @@ fn prompt_and_open_paths(app_state: Arc<AppState>, options: PathPromptOptions, c
 
 pub fn init(app_state: Arc<AppState>, cx: &mut App) {
     init_settings(cx);
+    component::init();
     theme_preview::init(cx);
 
     cx.on_action(Workspace::close_global);