2.6.3: Add tensor streaming, feature improvements

What's Changed

• [2.6] Fix integration test by @YuanTingHsieh in #3587
• [2.6] Update doc links to point to 2.6 by @YuanTingHsieh in #3792
• [2.6] Make admin server timeout configurable (#3786) by @YuanTingHsieh in #3791
• Add Tensor Stream component for efficient safetensors-based model tensor streaming by @rfilgueiras in #3828

Full Changelog: 2.6.2...2.6.3