Import josh-sync from subrepo/main

Sync-Origin: import/josh-sync/20260528-041502

tests/fixtures/minimal.yml

@@ -0,0 +1,18 @@
+# Test fixture: minimal single-target config
+schema_version: 2
+josh:
+  proxy_url: "https://josh.test.local"
+  monorepo_path: "org/repo"
+  monorepo_url: "git@gitea.test.local:org/repo.git"
+
+targets:
+  - name: "example"
+    subfolder: "services/example"
+    subrepo_url: "https://gitea.test.local/ext/example.git"
+    branches:
+      main: main
+
+bot:
+  name: "test-bot"
+  email: "test@test.local"
+  trailer: "Josh-Sync-Origin"