Merge branch 'fix/security-alerts' into dev

Closes 5 security alerts:
- Dependabot #88 (uuid <14)
- Dependabot #45 (postcss <8.5.10 transitive via next)
- CodeQL #103, #104 (workflow permissions)
- CodeQL #108 (vite injector strip)

Plus CodeQL paths-ignore for vendored bundles, shadow src, and local
audit tools.

Author: profvjreddi

.github/codeql/codeql-config.yml

@@ -0,0 +1,20 @@
+name: "MLSysBook CodeQL config"
+
+# Paths excluded from analysis. Each entry below is code that operates on
+# trusted local artifacts or is vendored from upstream — out of scope for
+# the web-facing security analyses CodeQL applies by default.
+paths-ignore:
+  # Vendored third-party widget bundle (minified output from upstream
+  # socratiQ collaborative-widget-bridge build). Not hand-edited; alerts
+  # here should be reported upstream, not patched in-tree.
+  - "book/quarto/tools/scripts/socratiQ/collaborative-widget-bridge.js"
+  - "book/quarto/tools/scripts/socratiQ/collaborative-widget-bridge.umd.cjs"
+
+  # Shadow copy of socratiq client source — parallel to socratiq/js/, kept
+  # for the shadow-DOM rendering path. Not part of the live web surface.
+  - "socratiq/src_shadow/**"
+
+  # Local audit/maintenance scripts that operate on the user's own Quarto
+  # build output. Not web-facing; regex-based HTML strip is intentional
+  # for speed and is safe given trusted input.
+  - "tools/audit/**"

.github/workflows/staffml-validate-vault.yml

@@ -51,6 +51,10 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.head_ref || github.run_id }}
   cancel-in-progress: true
 
+# Read-only token: jobs only checkout, install, lint, and test.
+permissions:
+  contents: read
+
 env:
   # Workflow-wide single source for paths and versions. See docs/CI-VARIABLES.md.
   # The `paths:` trigger filter is intentionally NOT vars-ified — GitHub Actions