Document lock ordering, fix test data races, correct stateMu guard

- Add doc comments clarifying Server.mu and completionState.stateMu are
  independent (no ordering constraint).
- Fix test using wrong lock (s.mu instead of stateMu) for lastLLMCall.
- Replace time.Sleep polling in 7 tests with s.inflight.Wait() to
  eliminate data races under -race.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

1 files changed, 2 insertions, 5 deletions

diff --git a/internal/lsp/chat_prompt_test.go b/internal/lsp/chat_prompt_test.go
index 1f7b266..3a1146f 100644
--- a/internal/lsp/chat_prompt_test.go
+++ b/internal/lsp/chat_prompt_test.go
@@ -3,7 +3,6 @@ package lsp
 import (
 	"bytes"
 	"testing"
-	"time"
 )
 
 func TestDetectAndHandleChat_UsesConfiguredSystemPrompt(t *testing.T) {
@@ -20,10 +19,8 @@ func TestDetectAndHandleChat_UsesConfiguredSystemPrompt(t *testing.T) {
 	// Line that should trigger chat: ends with '>' and previous char in prefixes
 	s.setDocument(uri, "help?>\n")
 	s.detectAndHandleChat(uri)
-	// Wait briefly for async goroutine to call Chat
-	for i := 0; i < 20 && len(cap.msgs) == 0; i++ {
-		time.Sleep(10 * time.Millisecond)
-	}
+	// Wait for the background chat goroutine to finish.
+	s.inflight.Wait()
 	if len(cap.msgs) == 0 {
 		t.Fatalf("expected Chat to be called")
 	}