fix(ci): pin third-party actions to full commit SHAs (#65)

fix(ci): pin third-party actions to full commit SHAs

The account's Actions policy requires a full-length SHA ref. A tag or
branch ref is refused at
startup — `startup_failure`, no jobs, "this workflow graph cannot be
shown" — so these workflows
could not run at all. This resolves each ref to the commit it currently
points at and records the
ref in a trailing comment, e.g. `actions/checkout@<sha> # v4`.

`dtolnay/rust-toolchain` takes its toolchain from the ref itself, so
those steps also gained an
explicit `with: toolchain:` input; without it, a SHA ref would silently
lose the channel.

No behaviour is intended to change beyond the pins.

Author: hyperpolymath

.github/workflows/codeql.yml

@@ -31,16 +31,16 @@ jobs:
             build-mode: none
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v7.0.1
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
 
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v4.38.0
+        uses: github/codeql-action/init@b96794f015dfd88f77b49b1c93e0fa7110f94c63  # v4.38.0
         with:
           languages: ${{ matrix.language }}
           build-mode: ${{ matrix.build-mode }}
 
       - name: Autobuild
-        uses: github/codeql-action/autobuild@v4.38.0
+        uses: github/codeql-action/autobuild@b96794f015dfd88f77b49b1c93e0fa7110f94c63  # v4.38.0
 
       - name: Perform CodeQL Analysis
-        uses: github/codeql-action/analyze@v4.38.0
+        uses: github/codeql-action/analyze@b96794f015dfd88f77b49b1c93e0fa7110f94c63  # v4.38.0

.github/workflows/governance.yml

@@ -23,7 +23,7 @@ jobs:
     permissions:
       contents: read
     steps:
-      - uses: actions/checkout@v7.0.1
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1  # v7.0.1
         with:
           persist-credentials: false
       - name: Check shell syntax and offline ruleset behaviour

.github/workflows/push-email-notify.yml

@@ -40,7 +40,7 @@ jobs:
     timeout-minutes: 5
     steps:
       - name: Send push notification email
-        uses: hyperpolymath/smtp-notify-action@v0.3.0 # NOSONAR — pin authority is actions.lock (sha1-ede1191ef6ff3ac02c4f4d9efdf837ee517e11d7)
+        uses: hyperpolymath/smtp-notify-action@22e7bdb322c430c1d0dac6b3bb307f4bb139d0be  # NOSONAR — pin authority is actions.lock (sha1-ede1191ef6ff3ac02c4f4d9efdf837ee517e11d7)
         with:
           server_address: ${{ secrets.SMTP_HOST }}
           server_port: ${{ secrets.SMTP_PORT }}