fix(ci): refresh standards reusable pins d135b05 -> 8813ecf

`Check Workflow Staleness` fails boj-server on a recency window (<=50
commits behind standards HEAD OR <=14 days old); d135b05 was 75 commits /
26 days behind, i.e. outside on both arms. Deleting the retired
scorecard-enforcer.yml in d3f61c7 cleared the other two rules, leaving
these two pins as the only remaining failures.

Scoped to exactly the two the gate names. check-workflow-staleness.sh
only inspects governance-reusable, hypatia-scan-reusable and
scorecard-reusable, which is why mirror.yml sits at the same d135b05 and
was NOT flagged -- re-pinning it would be unmeasured scope creep against
a reusable nothing has diffed.

Measured, not assumed, before moving:

  * governance-reusable: same 10 jobs before and after, so no new
    required check appears. The three gates that actually change
    behaviour were each run locally against this tree --
      Guix primary / Nix fallback  -> PASS (guix.scm present; the Nix
                                     fallback was never required, so the
                                     absent flake.nix is a non-issue)
      Code quality + docs          -> PASS (README + LICENSE + CONTRIBUTING)
      banned languages + Groovy    -> 0 tracked .groovy/.gradle files
    Both gates fetch their scripts from standards@main rather than from
    the pin, so these are the same scripts CI will run.

  * scorecard-reusable: the whole d135b05..8813ecf diff is an SPDX
    correction (PMPL-1.0-or-later -> MPL-2.0) plus timeout-minutes: 15.
    Worth stating because scorecard.yml has no `pull_request` trigger, so
    this PR's checks do not exercise it; the diff is the evidence, not a
    green tick. Its first real run is the next push to main.

Local verification: check-workflow-staleness.sh exits 0.

Author: hyperpolymath

.github/workflows/governance.yml

@@ -31,4 +31,4 @@ permissions:
 
 jobs:
   governance:
-    uses: hyperpolymath/standards/.github/workflows/governance-reusable.yml@d135b05bfc647d0c0fbfedc7e80f37ea50f49236
+    uses: hyperpolymath/standards/.github/workflows/governance-reusable.yml@8813ecf2a841335c9dc14c75cc46694722cd6d28

.github/workflows/scorecard.yml

@@ -33,4 +33,4 @@ jobs:
     permissions:
       security-events: write
       id-token: write
-    uses: hyperpolymath/standards/.github/workflows/scorecard-reusable.yml@d135b05bfc647d0c0fbfedc7e80f37ea50f49236
+    uses: hyperpolymath/standards/.github/workflows/scorecard-reusable.yml@8813ecf2a841335c9dc14c75cc46694722cd6d28