fix: reply in user's thread and prevent git credential hangs

Pass thread name through Add-ons response wrapper so bot replies stay
in the user's thread instead of posting top-level messages. Add
GIT_TERMINAL_PROMPT=0 to Dockerfile to prevent git from hanging on
credential prompts, which was blocking all requests under concurrency=1.

packages/a2a-server/src/chat-bridge/response-renderer.ts

@@ -71,6 +71,7 @@ export function extractToolApprovals(
 export function renderResponse(
   response: A2AResponse,
   threadKey?: string,
+  threadName?: string,
 ): ChatResponse {
   const parts = extractAllParts(response);
   const textContent = extractTextFromParts(parts);
@@ -145,8 +146,10 @@ export function renderResponse(
     chatResponse.cardsV2 = cards;
   }
 
-  if (threadKey) {
-    chatResponse.thread = { threadKey };
+  if (threadKey || threadName) {
+    chatResponse.thread = {};
+    if (threadKey) chatResponse.thread.threadKey = threadKey;
+    if (threadName) chatResponse.thread.name = threadName;
   }
 
   // Ensure we always return something