feat(cli): embed persistent PTY binaries from npm packages

[jlongster]

Summary

• add the published @opencode-ai/pty@0.1.8 package as an explicit Core and CLI dependency
• resolve the current platform executable directly from npm dependencies in Bun development, with no OPENCODE_PTY_BIN override or manual installation required
• resolve all six macOS/Linux architecture and libc-specific packages directly from node_modules for production embedding
• preserve Bun embedded extraction and Node SEA staging while deleting GitHub-release downloads, hardcoded archive checksums, and the separate binary cache
• preserve explicit cross-platform installation of both OpenTUI and PTY native packages
• keep the conditional persistent-PTY runtime import external in published Core builds

Verification

• full production Bun executable build, including real web assets
• full production Node SEA executable build, including real web assets and embedded PTY extraction
• verified extracted Node PTY reports opencode-pty 0.1.8 (protocol 6) and requires only GLIBC_2.29
• Core, CLI, and TUI typechecks
• persistent daemon tests, Node asset tests, Core package build, generated SDK check, and generated documentation check

Extracted from #44971 so the dependency/build infrastructure can land independently.