test(ci): reference shared action by branch ref to probe private cross-repo resolution

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: Ahmed Abbas

.github/workflows/dep-age-check.yml

@@ -13,8 +13,6 @@ jobs:
       - uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6.0.3
         with:
           fetch-depth: 0 # need the base ref to diff lockfiles
-      - uses: convertcom/supply-chain@1e6559ce3128a1c80f2bf5ad780c79ffa75af751 # seed
+      - uses: convertcom/supply-chain@main # TEST: branch ref (SHA pin restored once resolution confirmed)
         with:
-          # Warn-only for the initial bake; flip to `block` + required check
-          # once we've confirmed no false positives on main.
           mode: warn