release: 0.102.0 (#1532)

* feat(internal/types): support eagerly validating pydantic iterators

* ci: pin GitHub Actions to commit SHAs

Pin all GitHub Actions referenced in generated workflows (both
first-party `actions/*` and third-party) to immutable commit SHAs.
Updating pinned actions is now a deliberate codegen-side bump rather
than implicit on every workflow run.

* feat(api): Add BetaManagedAgentsSearchResultBlock types

* codegen metadata

* chore(api): spec updates

* feat(api): Add support for cache diagnostics beta

* release: 0.102.0

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Co-authored-by: stainless-app[bot] <142633134+stainless-app[bot]@users.noreply.github.com>