fix(ci): remove erroneous squisher-corpus guix.scm placeholder (#43)

Part of estate-wide standards#426 remediation - cleanup of
squisher-corpus placeholders that have no business being in this repo.

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## Summary by Gitar

- **CI workflow updates:**
- Added explicit `actions: read` permission to CodeQL and other workflow
configurations
- **Cleanup:**
    - Removed erroneous `guix.scm` placeholder file

<sub>This will update automatically on new commits.</sub>

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Co-authored-by: Mistral Vibe <vibe@mistral.ai>

Author: hyperpolymath

.github/workflows/scorecard.yml

@@ -9,6 +9,7 @@ on:
     branches: [main]
 
 permissions: read-all
+  actions: read
 
 jobs:
   analysis:

.github/workflows/secret-scanner.yml

@@ -15,6 +15,7 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true
 permissions:
+  actions: read
   contents: read
 jobs:
   scan: