refactor(core): migrate concrete runtime owners to services

[limityan]

Summary

• Move concrete runtime owners from bitfun-core into bitfun-services-integrations for remote SSH/SFTP/PTY, DeepResearch report IO, MiniApp host dispatch, built-in seed/marker IO, MiniApp JS worker/pool lifecycle, storage filesystem IO, and import bundle IO.
• Keep compatibility facades in core so existing call sites and public error shapes continue to work while the concrete implementation owner changes.
• Update boundary rules, self-tests, AGENTS guidance, and the core decomposition plan to reflect the new owner split and remaining high-risk runtime work.

Risk and impact

• No product behavior change is intended. Core still owns orchestration, event emission, compile workflow, and manager decisions; services owns reusable filesystem/process/protocol IO.
• Services-integrations was checked for no direct bitfun-core, PathManager, Tauri, or core event-emitter dependency.
• Remaining high-risk work is intentionally left out: DeepReview launch/provider wait/report persistence, scheduler/session side effects, tool pipeline concrete glue, and full MiniApp manager workflow ownership.

Verification

• node --test scripts/check-core-boundaries.test.mjs
• node scripts/check-core-boundaries.mjs
• pnpm run check:repo-hygiene
• git diff --check gcwing/main..HEAD
• cargo test -p bitfun-services-integrations --features miniapp-runtime miniapp
• cargo test -p bitfun-core --features product-full miniapp::manager
• cargo check -p bitfun-core --no-default-features
• cargo check -p bitfun-core --features product-full
• cargo check -p bitfun-services-integrations --no-default-features
• cargo check -p bitfun-services-integrations --features miniapp-runtime
• cargo check -p bitfun-cli
• cargo check -p bitfun-acp
• cargo check -p bitfun-desktop
• cargo metadata --no-deps --format-version 1