* fix: add PEP 561 py.typed marker to all Python packages
Add empty py.typed marker files to all 13 Python packages that were
missing them. Only hindsight-integrations/autogen already had one.
Per PEP 561, packages that wish to support type checking must include
a py.typed marker file. Without it, type checkers (mypy, pyright) treat
the package as untyped and skip all inline type annotations.
Fixes#965
* fix: ensure py.typed markers survive client regeneration
Add touch commands in generate-clients.sh to recreate PEP 561 py.typed
marker files after the OpenAPI generator runs, since the script deletes
and regenerates the hindsight_client_api directory.
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Co-authored-by: r266-tech <r266-tech@users.noreply.github.com>