security: remove hardcoded abiba-bot credentials from deploy workflow

Completes aeb79c6 (main): four more clone steps in deploy.yml still
embedded abiba-bot HTTP Basic credentials in plaintext. Runner already
auto-checkouts the repo, so the manual clone was redundant — replaced
with actions/checkout@v4, same pattern as ci.yml.

No secrets remain in tracked workflow files after this change.

.gitea/workflows/deploy.yml

@@ -21,7 +21,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        run: git clone --depth 1 http://abiba-bot:***REMOVED***@192.168.68.17:3000/SyslogSolution/zulip-platform-plugins.git .
+        uses: actions/checkout@v4
       - name: Python syntax
         run: |
           python3 -m py_compile plugins/platforms/zulip/adapter.py 2>/dev/null
@@ -37,7 +37,7 @@ jobs:
     environment: canary
     steps:
       - name: Checkout
-        run: git clone --depth 1 http://abiba-bot:***REMOVED***@192.168.68.17:3000/SyslogSolution/zulip-platform-plugins.git .
+        uses: actions/checkout@v4
       - name: Deploy to Tanko
         env:
           TAG: ${{ github.ref_name }}
@@ -66,7 +66,7 @@ jobs:
     environment: production
     steps:
       - name: Checkout
-        run: git clone --depth 1 http://abiba-bot:***REMOVED***@192.168.68.17:3000/SyslogSolution/zulip-platform-plugins.git .
+        uses: actions/checkout@v4
       - name: Deploy to all Hermes agents
         env:
           TAG: ${{ github.ref_name }}
@@ -97,7 +97,7 @@ jobs:
     environment: agent-zero
     steps:
       - name: Checkout
-        run: git clone --depth 1 http://abiba-bot:***REMOVED***@192.168.68.17:3000/SyslogSolution/zulip-platform-plugins.git .
+        uses: actions/checkout@v4
       - name: Deploy to kagentz
         env:
           TAG: ${{ github.ref_name }}