* fix(bootstrap): guard bootstrap name checks against undefined names
Add optional chaining to isAgentsBootstrapFile and isAgentsBootstrapName
to prevent TypeError: Cannot read properties of undefined (reading 'toLowerCase')
when bootstrap file entries have undefined name properties.
This crash was observed in 2026.5.20 where a workspace bootstrap file entry
with an undefined name caused every incoming message to fail during bootstrap
context building, completely blocking all agent replies.
Fixes#85523
* test(agents): cover unnamed bootstrap truncation entries
* test(agents): keep bootstrap truncation fixture typed
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Co-authored-by: Peter Steinberger <steipete@gmail.com>
25fa46bd61