feat: publish Gamertan Tend preview source

Sanitized root snapshot from private source commit a72903c63e1753f9e6ffbf40453c0830bdfc05c5 and tree 295641e67eef5979da76746d8ae271249568263e. Private development history and workflows are excluded by the exact allowlist.

AI-assisted: OpenAI Codex helped implement, test, and audit this preview.
Signed-off-by: Cole Speelman <crspeelman@gmail.com>

internal/deploy/ownership_linux.go

@@ -0,0 +1,38 @@
+//go:build linux
+
+// SPDX-License-Identifier: AGPL-3.0-only
+
+package deploy
+
+import (
+	"os"
+	"syscall"
+)
+
+type fileIdentity struct {
+	mode     os.FileMode
+	uid, gid int
+	owned    bool
+}
+
+func identityFor(info os.FileInfo, fallback os.FileMode) fileIdentity {
+	identity := fileIdentity{mode: fallback}
+	if info == nil {
+		return identity
+	}
+	identity.mode = info.Mode().Perm()
+	if stat, ok := info.Sys().(*syscall.Stat_t); ok {
+		identity.uid = int(stat.Uid)
+		identity.gid = int(stat.Gid)
+		identity.owned = true
+	}
+	return identity
+}
+func applyIdentity(file *os.File, identity fileIdentity) error {
+	if identity.owned {
+		if err := file.Chown(identity.uid, identity.gid); err != nil {
+			return err
+		}
+	}
+	return file.Chmod(identity.mode)
+}