[soulteary]

Windows CI had two independent failures:

• CMake release downloads returned HTTP 504 before configuration. Retry both the archive and checksum downloads up to five times with a five-second interval and 120-second request timeout, retaining mandatory SHA256 verification.
• The L20Lite configured-speed cache regression hit the default 100ms request deadline on a loaded Windows Release runner while checking an empty cache. Give this cache-semantics test an explicit two-second read budget, preserving all assertions and SDK defaults.

Validation: local Release C++ build passes; configured-speed tests pass (57 assertions across four cases), including the failing regression (14 assertions). All 39 release validation Python tests pass; documentation and helper checks pass (one platform-specific transport test skipped). PR workflows validate Windows and the full platform matrix.