feat: add display_report option to disable step summary (#952)

Add a `display_report` input parameter (default: "true") that controls
whether the Claude Code Report is written to the GitHub Step Summary.
Setting it to "false" allows users with custom formatting solutions to
avoid duplicate output in the step summary.

Closes #206

Co-authored-by: claude[bot] <41898282+claude[bot]@users.noreply.github.com>
Co-authored-by: Ashwin Bhat <ashwin-ant@users.noreply.github.com>

src/entrypoints/run.ts

@@ -295,8 +295,12 @@ async function run() {
       }
     }
 
-    // Write step summary
-    if (executionFile && existsSync(executionFile)) {
+    // Write step summary (unless display_report is set to false)
+    if (
+      executionFile &&
+      existsSync(executionFile) &&
+      process.env.DISPLAY_REPORT !== "false"
+    ) {
       await writeStepSummary(executionFile);
     }