fix(update): preserve archive metadata in git checkouts

- Skip expanded archive metadata when updating Git worktrees
- Retain commit metadata for archive-only installations
- Cover repositories, linked worktrees, and packaged installs

gui/main.py

@@ -131,6 +131,20 @@ class UpdateThread(QThread):
             return False
         return True
 
+    @classmethod
+    def should_install_to_root(cls, rel: Path, root: Path) -> bool:
+        """Return True when *rel* may be copied into the selected install root.
+
+        Git expands ``.git_archival.txt`` while creating a source archive. Keep
+        that expanded file in archive-only installs, but do not copy it back
+        into a live checkout where it would dirty the worktree on every update.
+        """
+        if not cls.should_install(rel):
+            return False
+        if rel.as_posix() == ".git_archival.txt" and (root / ".git").exists():
+            return False
+        return True
+
     @classmethod
     def resolve_archive_root(cls, extract_dir: Path) -> Path:
         """Locate the single top-level folder inside an extracted archive.
@@ -281,7 +295,11 @@ class UpdateThread(QThread):
             install_files = [
                 src
                 for src in extracted.rglob("*")
-                if src.is_file() and self.should_install(src.relative_to(extracted))
+                if src.is_file()
+                and self.should_install_to_root(
+                    src.relative_to(extracted),
+                    root,
+                )
             ]
             if not install_files:
                 raise RuntimeError(

tests/test_bundled_updates.py

@@ -68,6 +68,51 @@ class UpdateThreadInstallFilterTests(unittest.TestCase):
             with self.subTest(rel=rel):
                 self.assertFalse(UpdateThread.should_install(Path(rel)))
 
+    def test_preserves_archive_metadata_in_git_checkout(self):
+        from gui.main import UpdateThread
+
+        with tempfile.TemporaryDirectory() as raw:
+            root = Path(raw)
+            (root / ".git").mkdir()
+
+            self.assertFalse(
+                UpdateThread.should_install_to_root(
+                    Path(".git_archival.txt"),
+                    root,
+                )
+            )
+            self.assertTrue(
+                UpdateThread.should_install_to_root(Path("gui/main.py"), root)
+            )
+
+    def test_preserves_archive_metadata_with_git_file(self):
+        """Linked worktrees and submodules use a .git file, not a directory."""
+        from gui.main import UpdateThread
+
+        with tempfile.TemporaryDirectory() as raw:
+            root = Path(raw)
+            (root / ".git").write_text("gitdir: elsewhere\n", encoding="utf-8")
+
+            self.assertFalse(
+                UpdateThread.should_install_to_root(
+                    Path(".git_archival.txt"),
+                    root,
+                )
+            )
+
+    def test_installs_archive_metadata_outside_git_checkout(self):
+        from gui.main import UpdateThread
+
+        with tempfile.TemporaryDirectory() as raw:
+            root = Path(raw)
+
+            self.assertTrue(
+                UpdateThread.should_install_to_root(
+                    Path(".git_archival.txt"),
+                    root,
+                )
+            )
+
 
 class UpdateThreadArchiveRootTests(unittest.TestCase):
     """Gitea zips nest files under a single top folder (repo display name)."""