SMITH-021 Implement debugging presentation

[webfish0]

Outcome

DAP-backed debugging works through terminal views.

Scope

• Debug configuration/start flow.
• Breakpoints, call stack, threads, variables, watches, and debug console.
• Continue/pause/step/restart/stop controls and editor instruction markers.
• Reconnect/lost-session behavior.

Acceptance criteria

• T-017 and debug cases in T-019 pass with a real adapter.

Requirements: US-007, FR-010

Source: backlog.md SMITH-021.