zeta: Send staff edit predictions through Cloudflare Workers (#23847)

This PR makes it so staff edit predictions now go through Cloudflare
Workers instead of going to the LLM service.

This will allow us to dogfood the new LLM worker to make sure it is
working as expected.

Release Notes:

- N/A

crates/zeta/src/zeta.rs

@@ -8,6 +8,7 @@ use anyhow::{anyhow, Context as _, Result};
 use arrayvec::ArrayVec;
 use client::{Client, UserStore};
 use collections::{HashMap, HashSet, VecDeque};
+use feature_flags::FeatureFlagAppExt as _;
 use futures::AsyncReadExt;
 use gpui::{
     actions, App, AppContext as _, AsyncApp, Context, Entity, EntityId, Global, Subscription, Task,
@@ -298,7 +299,7 @@ impl Zeta {
         perform_predict_edits: F,
     ) -> Task<Result<Option<InlineCompletion>>>
     where
-        F: FnOnce(Arc<Client>, LlmApiToken, PredictEditsParams) -> R + 'static,
+        F: FnOnce(Arc<Client>, LlmApiToken, bool, PredictEditsParams) -> R + 'static,
         R: Future<Output = Result<PredictEditsResponse>> + Send + 'static,
     {
         let snapshot = self.report_changes_for_buffer(buffer, cx);
@@ -313,6 +314,7 @@ impl Zeta {
 
         let client = self.client.clone();
         let llm_token = self.llm_token.clone();
+        let is_staff = cx.is_staff();
 
         cx.spawn(|_, cx| async move {
             let request_sent_at = Instant::now();
@@ -348,7 +350,7 @@ impl Zeta {
                 outline: Some(input_outline.clone()),
             };
 
-            let response = perform_predict_edits(client, llm_token, body).await?;
+            let response = perform_predict_edits(client, llm_token, is_staff, body).await?;
 
             let output_excerpt = response.output_excerpt;
             log::debug!("completion response: {}", output_excerpt);
@@ -515,7 +517,7 @@ and then another
     ) -> Task<Result<Option<InlineCompletion>>> {
         use std::future::ready;
 
-        self.request_completion_impl(buffer, position, cx, |_, _, _| ready(Ok(response)))
+        self.request_completion_impl(buffer, position, cx, |_, _, _, _| ready(Ok(response)))
     }
 
     pub fn request_completion(
@@ -530,6 +532,7 @@ and then another
     fn perform_predict_edits(
         client: Arc<Client>,
         llm_token: LlmApiToken,
+        is_staff: bool,
         body: PredictEditsParams,
     ) -> impl Future<Output = Result<PredictEditsResponse>> {
         async move {
@@ -538,14 +541,19 @@ and then another
             let mut did_retry = false;
 
             loop {
-                let request_builder = http_client::Request::builder();
-                let request = request_builder
-                    .method(Method::POST)
-                    .uri(
+                let request_builder = http_client::Request::builder().method(Method::POST);
+                let request_builder = if is_staff {
+                    request_builder.uri(
+                        "https://llm-worker-production.zed-industries.workers.dev/predict_edits",
+                    )
+                } else {
+                    request_builder.uri(
                         http_client
                             .build_zed_llm_url("/predict_edits", &[])?
                             .as_ref(),
                     )
+                };
+                let request = request_builder
                     .header("Content-Type", "application/json")
                     .header("Authorization", format!("Bearer {}", token))
                     .body(serde_json::to_string(&body)?.into())?;