[Pingzii]

Three unit tests fail on Windows for reasons unrelated to what they check:

• tests/unit/compat/npu/test_ascend_config_lifecycle.py reads a source file with Path.read_text() and no encoding, so the GBK locale decodes UTF-8 bytes and raises UnicodeDecodeError; both reads now state UTF-8.
• tests/unit/package/test_cam_async_build.py builds its manifest file list with native separators while setuptools works on posix manifest paths, so every required entry misses; the list now uses as_posix().
• tests/unit/package/test_package.py needs installation metadata to find the vllm.general_plugins entry point, which a source tree does not have; it now skips with that reason, and still checks the entry point when the distribution is installed.

No production code changes. With these, full tests/unit on a Windows CPU host with torch and no vLLM is 900 passed / 89 skipped / 0 failed (previously 8 failed).
Where these come from, for review context:

• the six GBK failures: tests/unit/compat/npu/test_ascend_config_lifecycle.py arrived in Integrate vLLM 0.30.0 upgrade with current main #425 (b7561d7) with ast.parse(path.read_text()) and no encoding, so it is latent everywhere except a locale that cannot decode UTF-8;
• the manifest failure: test: prune redundant unit tests and preserve behavior coverage #539 (f2c79d8) replaced the posix-normalised required set with set(files.allfiles), whose entries carry native separators, so the comparison only holds where / is the separator. The Add routed-only asynchronous CAM operators to the AFD NPU build #361 version of the test compared normalised paths and was correct;
• the entry-point failure: the test first appeared as tests/test_package.py in Migrate AFD into external vLLM plugin #1 (dffdb14, "Add Phase 1 plugin skeleton") and was later moved to tests/unit/package/test_package.py by d1fd84f; it always needed installation metadata.

None of the three involves the transports in #506; the tests are older than that branch.
On verification scope: this PR's checks are label, pre-commit and DCO -- none of them installs the plugin or runs pytest. The numbers above come from a local run on this branch; the entry-point test exercising an installed build is therefore not covered by CI, before or after this change.