feat: add HarmonyOS OpenHarmony support

Harvest the HarmonyOS/OpenHarmony port from PR #2634 and make it publish-safe by target-gating unsupported host dependencies out of the OHOS TUI graph. Self-update is disabled on OHOS, PTY shell mode reports unsupported, and Starlark execpolicy parsing returns an explicit unsupported-platform error until upstream starlark/rustyline/nix support catches up.

Add OHOS SDK setup docs and launcher scripts, install the rustls ring provider for rustls-no-provider entrypoints, and keep the packaged codewhale-tui OHOS graph free of starlark, rustyline, nix@0.28, portable-pty, and arboard.

Validation: cargo fmt --all -- --check; git diff --check; git diff --cached --check; cargo check -p codewhale-cli --locked; cargo check -p codewhale-app-server --locked; cargo check -p codewhale-tui --locked; cargo test -p codewhale-cli --locked update::tests::; cargo test -p codewhale-release --locked; cargo test -p codewhale-tui --locked background_tty_command_has_controlling_terminal; cargo test -p codewhale-tui --locked clipboard; cargo package -p codewhale-tui --allow-dirty --no-verify --locked; packaged OHOS cargo tree checks. OHOS target check still requires a loaded OpenHarmony SDK/sysroot and currently stops in ring with missing assert.h when CC/CFLAGS/linker are unset.

Harvested from PR #2634 by @shenjackyuanjie.

Co-authored-by: shenjackyuanjie <54507071+shenjackyuanjie@users.noreply.github.com>

scripts/ohos-env.ps1

@@ -0,0 +1,57 @@
+$ErrorActionPreference = "Stop"
+
+function Stop-OhosEnv {
+    param([string]$Message)
+
+    [Console]::Error.WriteLine("error: $Message")
+    throw "OpenHarmony Cargo environment setup failed."
+}
+
+if ([string]::IsNullOrWhiteSpace($env:OHOS_NATIVE_SDK)) {
+    Stop-OhosEnv "set OHOS_NATIVE_SDK to the OpenHarmony native SDK directory."
+}
+
+if (-not (Test-Path -LiteralPath $env:OHOS_NATIVE_SDK -PathType Container -ErrorAction SilentlyContinue)) {
+    Stop-OhosEnv "OHOS_NATIVE_SDK does not exist: $env:OHOS_NATIVE_SDK"
+}
+
+$sdk = (Resolve-Path -LiteralPath $env:OHOS_NATIVE_SDK -ErrorAction Stop).Path
+$clang = [System.IO.Path]::Combine($sdk, "llvm", "bin", "clang.exe")
+$clangxx = [System.IO.Path]::Combine($sdk, "llvm", "bin", "clang++.exe")
+$ar = [System.IO.Path]::Combine($sdk, "llvm", "bin", "llvm-ar.exe")
+$sysroot = [System.IO.Path]::Combine($sdk, "sysroot")
+$cmakeToolchain = [System.IO.Path]::Combine($sdk, "build", "cmake", "ohos.toolchain.cmake")
+
+$requiredFiles = @($clang, $clangxx, $ar, $cmakeToolchain)
+foreach ($path in $requiredFiles) {
+    if (-not (Test-Path -LiteralPath $path -PathType Leaf -ErrorAction SilentlyContinue)) {
+        Stop-OhosEnv "required OpenHarmony SDK file is missing: $path"
+    }
+}
+
+if (-not (Test-Path -LiteralPath $sysroot -PathType Container -ErrorAction SilentlyContinue)) {
+    Stop-OhosEnv "required OpenHarmony SDK sysroot is missing: $sysroot"
+}
+
+$target = "aarch64_unknown_linux_ohos"
+$targetUpper = "AARCH64_UNKNOWN_LINUX_OHOS"
+$commonFlags = "-target aarch64-linux-ohos --sysroot=`"$sysroot`" -D__MUSL__"
+
+$env:CARGO_TARGET_AARCH64_UNKNOWN_LINUX_OHOS_LINKER = $clang
+$env:AR_aarch64_unknown_linux_ohos = $ar
+$env:CC_aarch64_unknown_linux_ohos = $clang
+$env:CXX_aarch64_unknown_linux_ohos = $clangxx
+$env:CC_SHELL_ESCAPED_FLAGS = "1"
+Set-Item -Path "Env:CFLAGS_$target" -Value $commonFlags
+Set-Item -Path "Env:CXXFLAGS_$target" -Value $commonFlags
+Set-Item -Path "Env:CMAKE_TOOLCHAIN_FILE_$target" -Value $cmakeToolchain
+
+$separator = [char]0x1f
+$env:CARGO_ENCODED_RUSTFLAGS = @(
+    "-Clink-arg=-target",
+    "-Clink-arg=aarch64-linux-ohos",
+    "-Clink-arg=--sysroot=$sysroot",
+    "-Clink-arg=-D__MUSL__"
+) -join $separator
+
+Write-Host "Configured OpenHarmony Cargo environment for $targetUpper from $sdk"

scripts/ohos-env.sh

@@ -0,0 +1,44 @@
+#!/usr/bin/env sh
+
+if [ -z "${OHOS_NATIVE_SDK:-}" ]; then
+    echo "error: set OHOS_NATIVE_SDK to the OpenHarmony native SDK directory." >&2
+    return 1 2>/dev/null || exit 1
+fi
+
+if [ ! -d "$OHOS_NATIVE_SDK" ]; then
+    echo "error: OHOS_NATIVE_SDK does not exist: $OHOS_NATIVE_SDK" >&2
+    return 1 2>/dev/null || exit 1
+fi
+
+sdk=$(cd "$OHOS_NATIVE_SDK" && pwd)
+clang=$sdk/llvm/bin/clang
+clangxx=$sdk/llvm/bin/clang++
+ar=$sdk/llvm/bin/llvm-ar
+sysroot=$sdk/sysroot
+cmake_toolchain=$sdk/build/cmake/ohos.toolchain.cmake
+
+for file in "$clang" "$clangxx" "$ar" "$cmake_toolchain"; do
+    if [ ! -f "$file" ]; then
+        echo "error: required OpenHarmony SDK file is missing: $file" >&2
+        return 1 2>/dev/null || exit 1
+    fi
+done
+
+if [ ! -d "$sysroot" ]; then
+    echo "error: required OpenHarmony SDK sysroot is missing: $sysroot" >&2
+    return 1 2>/dev/null || exit 1
+fi
+
+export CARGO_TARGET_AARCH64_UNKNOWN_LINUX_OHOS_LINKER=$clang
+export AR_aarch64_unknown_linux_ohos=$ar
+export CC_aarch64_unknown_linux_ohos=$clang
+export CXX_aarch64_unknown_linux_ohos=$clangxx
+export CC_SHELL_ESCAPED_FLAGS=1
+export CFLAGS_aarch64_unknown_linux_ohos="-target aarch64-linux-ohos --sysroot=\"$sysroot\" -D__MUSL__"
+export CXXFLAGS_aarch64_unknown_linux_ohos="-target aarch64-linux-ohos --sysroot=\"$sysroot\" -D__MUSL__"
+export CMAKE_TOOLCHAIN_FILE_aarch64_unknown_linux_ohos=$cmake_toolchain
+
+sep=$(printf '\037')
+export CARGO_ENCODED_RUSTFLAGS="-Clink-arg=-target${sep}-Clink-arg=aarch64-linux-ohos${sep}-Clink-arg=--sysroot=$sysroot${sep}-Clink-arg=-D__MUSL__"
+
+echo "Configured OpenHarmony Cargo environment for AARCH64_UNKNOWN_LINUX_OHOS from $sdk"