feat: add agent-driven debugging

[shanejonas]

What changed

• add an OpenRPC control plane with revision-based change waiting
• add shared line ranges, visible gutters, mouse focus, and panel scrolling
• add safe session export and history replay
• keep the TUI responsive with background requests and an inline Vim-style editor
• separate CI from tag-gated crate and GitHub releases

Proof

• cargo test --all-targets
• cargo clippy --all-targets --all-features -- -D warnings
• cargo package --locked
• 24 OpenRPC runtime coverage calls
• isolated live wait, replay, and skill demo