assistant2: Do not allow a context entry to be added multiple times (#22712)

https://github.com/user-attachments/assets/81674c88-031b-4d55-b362-43819492b93d


Release Notes:

- N/A

crates/assistant2/src/context.rs

@@ -1,11 +1,8 @@
 use gpui::SharedString;
 use language_model::{LanguageModelRequestMessage, MessageContent};
-use project::ProjectEntryId;
 use serde::{Deserialize, Serialize};
 use util::post_inc;
 
-use crate::thread::ThreadId;
-
 #[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Hash, Clone, Copy, Serialize, Deserialize)]
 pub struct ContextId(pub(crate) usize);
 
@@ -26,10 +23,10 @@ pub struct Context {
 
 #[derive(Debug, Clone, PartialEq, Eq, Hash)]
 pub enum ContextKind {
-    File(ProjectEntryId),
+    File,
     Directory,
     FetchedUrl,
-    Thread(ThreadId),
+    Thread,
 }
 
 pub fn attach_context_to_message(
@@ -43,7 +40,7 @@ pub fn attach_context_to_message(
 
     for context in context.into_iter() {
         match context.kind {
-            ContextKind::File(_) => {
+            ContextKind::File => {
                 file_context.push_str(&context.text);
                 file_context.push('\n');
             }
@@ -57,7 +54,7 @@ pub fn attach_context_to_message(
                 fetch_context.push_str(&context.text);
                 fetch_context.push('\n');
             }
-            ContextKind::Thread(_) => {
+            ContextKind::Thread => {
                 thread_context.push_str(&context.name);
                 thread_context.push('\n');
                 thread_context.push_str(&context.text);