Track incremental WTA architecture refactoring

[vanzue]

Goal

Incrementally improve WTA module ownership and dependency direction while preserving existing behavior. Keep each change independently reviewable and releasable.

Current work

• Refactor WTA helper runtime ownership #504 — move helper runtime ownership out of main.rs
• Extract WTA app contracts #507 — extract shared App contracts and remove the ACP client's dependency on app
• Extract WTA tab state and input editing #514 — extract per-tab state and input editing from app.rs
• Move WTA failure classification into ACP domain #517 — move failure classification into the ACP domain
• Separate WTA CLI arguments from runtime configuration #519 — separate CLI arguments from helper/master runtime configuration
• Extract WTA probe, hooks, and sessions CLI handlers #523 — extract probe, hooks, and sessions CLI handlers from main.rs

Future refactors will be added here as their scope is reviewed.