fix(agents): skip bootstrap files with undefined path (#22698)

* fix(agents): skip bootstrap files with undefined path

buildBootstrapContextFiles() called file.path.replace() without checking
that path was defined. If a hook pushed a bootstrap file using 'filePath'
instead of 'path', the function threw TypeError and crashed every agent
session — not just the misconfigured hook.

Fix: add a null-guard before the path.replace() call. Files with undefined
path are skipped with a warning so one bad hook can't take down all agents.

Also adds a test covering the undefined-path case.

Fixes #22693

* fix: harden bootstrap path validation and report guards (#22698) (thanks @arosstale)

---------

Co-authored-by: Peter Steinberger <steipete@gmail.com>

src/agents/pi-embedded-helpers/bootstrap.ts

@@ -199,15 +199,22 @@ export function buildBootstrapContextFiles(
     if (remainingTotalChars <= 0) {
       break;
     }
+    const pathValue = typeof file.path === "string" ? file.path.trim() : "";
+    if (!pathValue) {
+      opts?.warn?.(
+        `skipping bootstrap file "${file.name}" — missing or invalid "path" field (hook may have used "filePath" instead)`,
+      );
+      continue;
+    }
     if (file.missing) {
-      const missingText = `[MISSING] Expected at: ${file.path}`;
+      const missingText = `[MISSING] Expected at: ${pathValue}`;
       const cappedMissingText = clampToBudget(missingText, remainingTotalChars);
       if (!cappedMissingText) {
         break;
       }
       remainingTotalChars = Math.max(0, remainingTotalChars - cappedMissingText.length);
       result.push({
-        path: file.path,
+        path: pathValue,
         content: cappedMissingText,
       });
       continue;
@@ -231,7 +238,7 @@ export function buildBootstrapContextFiles(
     }
     remainingTotalChars = Math.max(0, remainingTotalChars - contentWithinBudget.length);
     result.push({
-      path: file.path,
+      path: pathValue,
       content: contentWithinBudget,
     });
   }