collab: Add the ability to filter extensions by what they provide (#24315)

This PR adds the ability to filter extension results from the extension
API by the features that they provide.

For instance, to filter down just to extensions that provide icon
themes:

```
https://api.zed.dev/extensions?provides=icon-themes
```

Release Notes:

- N/A

crates/collab/src/api/extensions.rs

@@ -9,10 +9,11 @@ use axum::{
     routing::get,
     Extension, Json, Router,
 };
-use collections::HashMap;
-use rpc::{ExtensionApiManifest, GetExtensionsResponse};
+use collections::{BTreeSet, HashMap};
+use rpc::{ExtensionApiManifest, ExtensionProvides, GetExtensionsResponse};
 use semantic_version::SemanticVersion;
 use serde::Deserialize;
+use std::str::FromStr;
 use std::{sync::Arc, time::Duration};
 use time::PrimitiveDateTime;
 use util::{maybe, ResultExt};
@@ -35,6 +36,14 @@ pub fn router() -> Router {
 #[derive(Debug, Deserialize)]
 struct GetExtensionsParams {
     filter: Option<String>,
+    /// A comma-delimited list of features that the extension must provide.
+    ///
+    /// For example:
+    /// - `themes`
+    /// - `themes,icon-themes`
+    /// - `languages,language-servers`
+    #[serde(default)]
+    provides: Option<String>,
     #[serde(default)]
     max_schema_version: i32,
 }
@@ -43,9 +52,22 @@ async fn get_extensions(
     Extension(app): Extension<Arc<AppState>>,
     Query(params): Query<GetExtensionsParams>,
 ) -> Result<Json<GetExtensionsResponse>> {
+    let provides_filter = params.provides.map(|provides| {
+        provides
+            .split(',')
+            .map(|value| value.trim())
+            .filter_map(|value| ExtensionProvides::from_str(value).ok())
+            .collect::<BTreeSet<_>>()
+    });
+
     let mut extensions = app
         .db
-        .get_extensions(params.filter.as_deref(), params.max_schema_version, 500)
+        .get_extensions(
+            params.filter.as_deref(),
+            provides_filter.as_ref(),
+            params.max_schema_version,
+            500,
+        )
         .await?;
 
     if let Some(filter) = params.filter.as_deref() {