Fix secrets context in workflow if-conditions across all workflows

GitHub Actions does not allow secrets in if-expressions. Use env vars
with shell-level empty check instead.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: 2 people

.github/workflows/ci.yml

@@ -72,9 +72,11 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Notify Slack on failure
-        if: ${{ secrets.SLACK_WEBHOOK_URL != '' }}
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
         run: |
-          curl -s -X POST "${{ secrets.SLACK_WEBHOOK_URL }}" \
+          [ -z "$SLACK_WEBHOOK_URL" ] && exit 0
+          curl -s -X POST "$SLACK_WEBHOOK_URL" \
             -H 'Content-Type: application/json' \
             -d '{
               "blocks": [

.github/workflows/deploy-api.yml

@@ -96,9 +96,12 @@ jobs:
           echo "URL: $URL" >> $GITHUB_STEP_SUMMARY
 
       - name: Notify Slack on failure
-        if: failure() && secrets.SLACK_WEBHOOK_URL != ''
+        if: failure()
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
         run: |
-          curl -s -X POST "${{ secrets.SLACK_WEBHOOK_URL }}" \
+          [ -z "$SLACK_WEBHOOK_URL" ] && exit 0
+          curl -s -X POST "$SLACK_WEBHOOK_URL" \
             -H 'Content-Type: application/json' \
             -d '{
               "blocks": [

.github/workflows/deploy-preview.yml

@@ -186,9 +186,11 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Notify Slack on failure
-        if: ${{ secrets.SLACK_WEBHOOK_URL != '' }}
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
         run: |
-          curl -s -X POST "${{ secrets.SLACK_WEBHOOK_URL }}" \
+          [ -z "$SLACK_WEBHOOK_URL" ] && exit 0
+          curl -s -X POST "$SLACK_WEBHOOK_URL" \
             -H 'Content-Type: application/json' \
             -d '{
               "blocks": [

.github/workflows/deploy-web.yml

@@ -103,9 +103,12 @@ jobs:
           echo "URL: $URL" >> $GITHUB_STEP_SUMMARY
 
       - name: Notify Slack on failure
-        if: failure() && secrets.SLACK_WEBHOOK_URL != ''
+        if: failure()
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
         run: |
-          curl -s -X POST "${{ secrets.SLACK_WEBHOOK_URL }}" \
+          [ -z "$SLACK_WEBHOOK_URL" ] && exit 0
+          curl -s -X POST "$SLACK_WEBHOOK_URL" \
             -H 'Content-Type: application/json' \
             -d '{
               "blocks": [

.github/workflows/infra-apply.yml

@@ -52,9 +52,12 @@ jobs:
           echo "Applied by: @${{ github.actor }}" >> $GITHUB_STEP_SUMMARY
 
       - name: Notify Slack on failure
-        if: failure() && secrets.SLACK_WEBHOOK_URL != ''
+        if: failure()
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
         run: |
-          curl -s -X POST "${{ secrets.SLACK_WEBHOOK_URL }}" \
+          [ -z "$SLACK_WEBHOOK_URL" ] && exit 0
+          curl -s -X POST "$SLACK_WEBHOOK_URL" \
             -H 'Content-Type: application/json' \
             -d '{
               "blocks": [

.github/workflows/infra-plan.yml

@@ -108,9 +108,12 @@ jobs:
             }
 
       - name: Notify Slack on failure
-        if: failure() && secrets.SLACK_WEBHOOK_URL != ''
+        if: failure()
+        env:
+          SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
         run: |
-          curl -s -X POST "${{ secrets.SLACK_WEBHOOK_URL }}" \
+          [ -z "$SLACK_WEBHOOK_URL" ] && exit 0
+          curl -s -X POST "$SLACK_WEBHOOK_URL" \
             -H 'Content-Type: application/json' \
             -d '{
               "blocks": [