fix(ci): drop the retired inline trufflehog job

secret-scanner-reusable.yml deliberately retired TruffleHog as redundant
("gitleaks provides sufficient coverage at lower cost" — see the reusable's
header). The inline job survived here, fails, and turns the whole Secret
Scanner workflow red even though gitleaks, rust-secrets and shell-secrets all
pass — so the repo keeps emitting ci_activity notifications.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: hyperpolymath

.github/workflows/secret-scanner.yml

@@ -17,13 +17,3 @@ jobs:
       actions: read
     uses: hyperpolymath/standards/.github/workflows/secret-scanner-reusable.yml@d135b05bfc647d0c0fbfedc7e80f37ea50f49236
     secrets: inherit
-  trufflehog:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-        with:
-          fetch-depth: 0
-      - name: TruffleHog Secret Scan
-        uses: trufflesecurity/trufflehog@main
-        with:
-          extra_args: --only-verified --fail