[richerfu]

OHOS targets report target_os = "linux". Desktop Linux dependencies and entrypoints must also exclude target_env = "ohos", otherwise an OHOS build resolves GTK/WebKit and desktop runners.

This changes the target guards in nsh-platform-linux, nsh-linux-host and nsh-linux-app, preserving the current Linux feature selections.

Part 1 of the draft stack: #473 → #474 → #475. All three target main; the later PRs include the earlier commits. Rebased onto 201d780a and kept as drafts for upstream review.

Validation

Validation on the combined stack:

• cargo test --workspace
• cargo clippy --workspace --all-targets -- -D warnings
• cargo xtask clippy-ohos (default, dev, API 23 and API 26)
• cargo xtask ohos --dev (API 20 compilation, linking and SDK staging)
• uv run --with PyYAML python .github/ci/paths.py

Desktop Linux execution was not repeated on this macOS host. Full-workspace formatting reports existing differences in unchanged upstream files; the changed OHOS files are formatted.

cargo xtask compat: 19 checks passed; checkout_apps_run failed in four existing scenarios (base Bold frame, macOS Dock tab contents, gallery Stocks row height, and hopper flight-history text). All four failures reproduce identically on unmodified upstream e239619b (the previous base); no fixture or demo was changed to suppress them.

After the final main refresh, cargo test -p nsh-core -p nsh-engine -p nsh-platform-ohos passed, including all 68 OHOS host tests. DataTable column interaction tests passed on upstream and this stack with --trace: 15 commits and 428 mount items in both runs.