[Rebase] Rebase to vllm 0.28.0 (#6606)

Signed-off-by: tzhouam <tzhouam@connect.ust.hk>
Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

examples/__init__.py

@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
+
+"""vLLM-Omni example scripts, importable as a package.
+
+Keep this ``__init__.py``: with the upstream vLLM installed editable (which also
+places an ``examples`` package on ``sys.path``), a regular package at this repo
+root wins over the upstream ``examples`` namespace during ``import examples``.
+"""