fix(daemon): add Windows autostart management

[legend91019]

Summary

Fixes #337.

Adds per-user Windows logon autostart management for the foreground BrowserSkill daemon and documents the daemon idle-exit behavior.

What changed

• Add bsk daemon install-autostart.
• Add bsk daemon uninstall-autostart.
• Generate a managed Startup-folder VBScript that runs bsk daemon start --foreground.
• Keep generated VBScript ASCII-safe, including executable paths containing Unicode characters.
• Make install, update, and uninstall idempotent.
• Refuse to overwrite or remove an unmanaged file with the same launcher name.
• Add CLI parsing and autostart behavior tests.
• Document Windows setup and the default ten-minute idle timeout in English and Chinese README files.

Verification

• cargo test -p bsk --test cli_parse parses_daemon_autostart_commands — passed.
• cargo test -p bsk daemon_autostart — passed; 3 autostart unit tests passed.
• cargo fmt --all -- --check — passed.
• cargo build --workspace --locked — passed with existing unused-parameter warnings in file_transfer.rs.
• cargo clippy --workspace --all-targets --locked -- -D warnings — blocked by existing warnings in file_transfer.rs and skill_install/harness.rs; the new autostart module produced no clippy errors.

The detailed Chinese review dossier is maintained locally at D:\Desktop\open_coding\pr_reviews\Tencent__BrowserSkill__337.md.

Scope

The implementation is Windows-only for autostart installation. Other platforms return an explicit unsupported-platform error. No protocol or browser-extension behavior is changed.