* chore: bump dependency floors for starlette form() DoS fix

Raise starlette to >=1.3.1 to pull in the CVE-2026-54283 form() DoS fix,
and exempt it from the workspace exclude so the floor resolves before it
ages out of the exclude-newer window. Also bump granian to >=2.7.4,
python-multipart to >=0.0.30, and vite to 8.0.16.

* chore: add changelog entries for security dependency bumps

Document the floor bumps for starlette/python-multipart/granian
(#6665) and the bundled vite dev dependency bump for CVE-2026-53571.

* chore: raise python-multipart floor to 0.0.32 for parse_form fixes

Pulls in fixes for unbounded header field size and negative
Content-Length buffering in parse_form, alongside the existing
quadratic-time querystring DoS fix.