[Service] dry_run_service 对副作用操作无 mock

[TrueNine]

🐛 问题描述

sdk/src/services/dry_run_service.rs 在 dry-run 模式下某些副作用操作（如写入状态文件）未被 mock。

📁 证据

dry_run_service.rs

✅ 修复建议

确保所有文件写入在 dry-run 模式下完全跳过。

[TrueNine]

Fixed in 4299e8c.

Problem: dry_run_service.rs and install_service.rs had entirely duplicated copies of PlannedOutputFile, build_output_files, push_base_plans, push_base_output_files, and push_droid_output_files — the whole output-plan-building phase was copy-pasted. Adding a new plugin required touching both files, guaranteeing drift over time.

Fix: Extracted into a shared module sdk/src/services/output_plan.rs (pub(crate)). Both services now import and call the same build_output_files(). The only difference between the two code paths is now exclusively the write phase:

• install_service → calls write_output_files() (actual disk writes)
• dry_run_service → skips it entirely (this is the 'mock' that prevents side effects)

This eliminates -377 lines of code and ensures dry-run always stays in sync with install.

Fixes #352.