Stop tracking the chat transcript the app writes into the repo

Launching the app from the working copy left .cowork_history/ next to the
source, and one transcript rode along into the previous commit and up to the
remote. It is the user's data, not code. Untracked and ignored, along with
.cowork_local/ for the same reason.

The file stays in the history of e5bd679 — removing it there rewrites the
branch, which is the user's call.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

.cowork_history/cowork__20260818-130950-831.json

@@ -1,16 +0,0 @@
-{
-  "kind": "cowork",
-  "session_id": "20260818-130950-831",
-  "title": "alo",
-  "created": "2026-08-18T13:10:03",
-  "pinned": false,
-  "project_id": "project-mới",
-  "inputs": [],
-  "outputs": [],
-  "messages": [
-    {
-      "role": "user",
-      "content": "alo"
-    }
-  ]
-}

.gitignore

@@ -116,3 +116,7 @@ vibeflow.json
 .turbo/
 *.tsbuildinfo
 
+# Runtime data the app writes next to itself when it is run from the repo.
+# A chat transcript got committed and pushed this way.
+.cowork_history/
+.cowork_local/