ci: refresh standards reusable pins to current HEAD (e9c8888) (#326)

## Summary

Brings the remaining standards reusable pins to current standards `main`
(`e9c8888`). The scan pin was bumped in #325; this completes the
refresh:

| Workflow | was | now |
|---|---|---|
| `governance.yml` | `d7c2271` | `e9c8888` (date comment refreshed →
`2026-06-27`) |
| `secret-scanner.yml` | `d135b05` | `e9c8888` |
| `scorecard.yml` | `d7c2271` | `e9c8888` |
| `mirror.yml` | `d135b05` | `e9c8888` |

This wires the source-pinned scanner cache fix (standards#441) into the
governance reusable used here. Scan-only change — fleet
actuation/dispatch
uses `HYPATIA_DISPATCH_PAT` (separate token) and is unaffected.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---
_Generated by [Claude
Code](https://claude.ai/code/session_017wGTeLwiBGJ5rETC3QT4Pm)_

Co-authored-by: Claude <noreply@anthropic.com>

Author: hyperpolymath

.github/workflows/governance.yml

@@ -31,5 +31,5 @@ permissions:
 
 jobs:
   governance:
-    uses: hyperpolymath/standards/.github/workflows/governance-reusable.yml@d7c22711e830e1f383846472f6e9b99debdb201e # main 2026-06-02
+    uses: hyperpolymath/standards/.github/workflows/governance-reusable.yml@e9c8888769a703924cc3c0d717900960d78aea00 # main 2026-06-27
     timeout-minutes: 30

.github/workflows/mirror.yml

@@ -11,6 +11,6 @@ permissions:
 
 jobs:
   mirror:
-    uses: hyperpolymath/standards/.github/workflows/mirror-reusable.yml@d135b05bfc647d0c0fbfedc7e80f37ea50f49236
+    uses: hyperpolymath/standards/.github/workflows/mirror-reusable.yml@e9c8888769a703924cc3c0d717900960d78aea00
     secrets: inherit
     timeout-minutes: 60

.github/workflows/scorecard.yml

@@ -15,6 +15,6 @@ jobs:
     permissions:
       security-events: write
       id-token: write
-    uses: hyperpolymath/standards/.github/workflows/scorecard-reusable.yml@d7c22711e830e1f383846472f6e9b99debdb201e
+    uses: hyperpolymath/standards/.github/workflows/scorecard-reusable.yml@e9c8888769a703924cc3c0d717900960d78aea00
     secrets: inherit
     timeout-minutes: 20

.github/workflows/secret-scanner.yml

@@ -15,6 +15,6 @@ permissions:
 
 jobs:
   scan:
-    uses: hyperpolymath/standards/.github/workflows/secret-scanner-reusable.yml@d135b05bfc647d0c0fbfedc7e80f37ea50f49236
+    uses: hyperpolymath/standards/.github/workflows/secret-scanner-reusable.yml@e9c8888769a703924cc3c0d717900960d78aea00
     secrets: inherit
     timeout-minutes: 20