feat!(report): generate JSON instead of markdown

This allows us to analyze the report more easily. There is experimental
support for comparing against a base report, but we don't expose that
functionality to the action.

action.yml

@@ -28,59 +28,21 @@ inputs:
     default: 'false'
   artifact-name:
     description: The name of the generated artifact.
-    default: 'size-report.md'
+    default: report.json
 outputs:
 runs:
   using: 'composite'
   steps:
     - name: Create report
       run: |
-        "$GITHUB_ACTION_PATH/create-report.sh"
+        "$GITHUB_ACTION_PATH/create-report.sh" > report.json
     - name: Upload Artifact
       uses: https://code.forgejo.org/forgejo/upload-artifact@v4
       if: inputs.generate-artifact == 'true'
       with:
-        path: size-report.md
+        path: report.json
         name: ${{ inputs.artifact-name }}
     - name: Comment Report
       if: inputs.comment-on-pr == 'true'
       run: |
-        set -eu
-
-        echo 'Determine head_ref'
-        # For push & tag events it'll bet GITHUB_REF_NAME, for pull_request events it'll be GITHUB_HEAD_REF
-        head_ref=${GITHUB_REF_NAME-$GITHUB_HEAD_REF}
-
-        echo "Get PR number for $head_ref"
-        prs=$(curl -X 'GET' \
-                "$GITHUB_API_URL/repos/$GITHUB_REPOSITORY/pulls?state=open&sort=recentupdate" \
-                -H "Authorization: token $GITHUB_TOKEN" \
-                -H 'accept: application/json')
-
-        pr_number=$(echo "$prs" |
-                jq --arg head_ref "$head_ref" '.[] | select(.head.ref == $head_ref) | .number')
-
-        # Protect against running before a PR is made or if it is triggered on the main branch
-        if [ -z "$pr_number" ]; then
-                echo "No PR created for this commit"
-                exit 0
-        fi
-
-        echo "Retrieved index: $pr_number" >&2
-        echo "Expected PR URL: $GITHUB_SERVER_URL/$GITHUB_REPOSITORY/pulls/$pr_number" >&2
-
-        echo 'Generating comment body' >&2
-        comment=$(cat size-report.md)
-
-        echo 'Posting comment:' >&2
-        echo "$comment" >&2
-
-        echo 'Request data:' >&2
-        data=$(echo '{}' | jq --arg comment "$comment" '.body=$comment')
-        echo "$data" >&2
-        curl -o - -X 'POST' \
-                "$GITHUB_API_URL/repos/$GITHUB_REPOSITORY/issues/$pr_number/comments" \
-                -H 'accept: application/json' \
-                -H "Authorization: token $GITHUB_TOKEN" \
-                -H 'Content-Type: application/json' \
-                -d "$data"
+        "$GITHUB_ACTION_PATH/comment_on_pr.sh" report.json