fix: set group-write permission on files after chown in multi-user mode

_chown() transferred file ownership to the provisioned user but didn't
set group-write permission, leaving files at 644. The server process
(a group member) could create new files but couldn't overwrite them on
subsequent saves, returning PermissionError. Now sets chmod g+w after
chown, matching the 2770 treatment already applied to directories.

Fixes #93

Author: tjbck

CHANGELOG.md

@@ -4,6 +4,12 @@ All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/).
 
+## [0.11.29] - 2026-03-24
+
+### Fixed
+
+- 🔒 **File save fails in multi-user mode** — `_chown()` transferred file ownership to the provisioned user but didn't set group-write permission, leaving files at `644`. The server process (a group member) could create new files but couldn't overwrite them on subsequent saves, returning `PermissionError`. Now sets `chmod g+w` after `chown`, matching the `2770` treatment already applied to directories. ([#93](https://github.com/open-webui/open-terminal/issues/93))
+
 ## [0.11.28] - 2026-03-24
 
 ### Added

open_terminal/utils/fs.py

@@ -90,13 +90,23 @@ def _check_path(self, path: str) -> None:
             )
 
     async def _chown(self, path: str) -> None:
-        """Fix ownership of *path* to the provisioned user."""
+        """Fix ownership of *path* to the provisioned user.
+
+        Also sets group-write permission so the server process (which is
+        in the provisioned user's group) can overwrite the file on
+        subsequent writes.
+        """
         if self.username:
             await asyncio.to_thread(
                 subprocess.run,
                 ["sudo", "chown", f"{self.username}:{self.username}", path],
                 check=True, capture_output=True,
             )
+            await asyncio.to_thread(
+                subprocess.run,
+                ["sudo", "chmod", "g+w", path],
+                check=True, capture_output=True,
+            )
 
     async def _ensure_parents(self, path: str) -> None:
         """Create parent directories for *path* with correct permissions.

pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "open-terminal"
-version = "0.11.28"
+version = "0.11.29"
 description = "A remote terminal API."
 readme = "README.md"
 authors = [