refactor(runtime-ports): complete HR-C contract closure

[limityan]

Summary

• Move HR-C portable service/agent contracts into bitfun-runtime-ports, including dialog reply/steering contracts, round injection contracts, goal-mode DTOs, compression contract facts, and workspace related-path facts.
• Keep existing bitfun-core import paths as compatibility re-exports so callers do not need behavior-level changes.
• Extend boundary checks and documentation so concrete runtime owners remain explicit core-owned paths unless they get separate protected migrations.

Non-goals

• Does not move remote-SSH, terminal adapters, scheduler lifecycle, agent registry, workspace-root/persistence, or ImageContextData concrete runtime behavior.
• Does not change product feature sets, release scripts, product surfaces, or user-visible command semantics.

Validation

• cargo test -p bitfun-runtime-ports -- --nocapture
• cargo test -p bitfun-core agentic::goal_mode -- --nocapture
• cargo test -p bitfun-core agentic::round_preempt::steering_tests -- --nocapture
• cargo test -p bitfun-core agentic::session::compression -- --nocapture
• cargo test -p bitfun-core agentic::agents::prompt_builder -- --nocapture
• node scripts\check-core-boundaries.mjs
• cargo check -p bitfun-core --features product-full
• cargo check --workspace
• git diff --check