fix(ci): run security chain evidence from the lane's own checkout (#8229)

The security workflow checks the repository out into rustfs-repo/ (#7212)
but its chain evidence steps still invoke
scripts/functional_chain_evidence.py relative to the workspace root, which
on the persistent shared runner resolves to a stale checkout left by another
job. The evidence gate then compares that checkout's HEAD against the chain
workflow_sha and rejects the lane before any case runs
("lane checkout differs from chain workflow source").

Run the evidence script from the lane's own checkout so ROOT resolves to
rustfs-repo/, whose HEAD is exactly the chain-pinned workflow_sha.

.github/workflows/rustfs-security-test.yml

@@ -106,7 +106,7 @@ jobs:
         if: ${{ inputs.chain_manifest != '' }}
         env:
           CHAIN_MANIFEST: ${{ inputs.chain_manifest }}
-        run: python3 scripts/functional_chain_evidence.py consume
+        run: python3 rustfs-repo/scripts/functional_chain_evidence.py consume
 
       - name: Checkout auto-testing scripts
         uses: actions/checkout@f548e57e544e1ff5a4c46bf1e1b8685f8e4a348a # v7
@@ -389,7 +389,7 @@ jobs:
           CHAIN_TEST_OUTCOME: ${{ steps.test.outcome }}
           CHAIN_REPORT_OUTCOME: ${{ steps.report.outcome }}
         run: >-
-          python3 scripts/functional_chain_evidence.py record --suite security
+          python3 rustfs-repo/scripts/functional_chain_evidence.py record --suite security
           --report "${SECURITY_ARTIFACTS_DIR}/suite-report.md"
           --output "${RUNNER_TEMP}/chain-security-${GITHUB_RUN_ID}-${GITHUB_RUN_ATTEMPT}/security.json"