feat: instance dialog uses AllowedRepo selector (replaces gitRepo/gitBranch inputs)

- Create Instance dialog now fetches repos from /api/aos/repos?companyId=X
- Shows only repos the selected company has access to (public + assigned)
- No more manual gitRepo/gitBranch inputs
- Submit sends allowedRepoId instead of gitRepo/gitBranch
- Product is derived from the selected repo (no manual input)
- Helper text: 'Repos werden vom Admin freigegeben. Quelle: Gitea, Branch: main.'

.zscripts/dev.pid

@@ -1 +1 @@
-1114
+1242