fix(qoder): route asks through visible panes

[imhjf]

Summary

• route qoder and qoderclicn asks through the exact managed visible pane
• validate the agent session and owned tmux pane before prompt delivery
• fail closed when the pane is unavailable instead of starting a hidden print process
• switch completion metadata to anchored terminal-text evidence and update contracts

Tests

• 188 focused Qoder/runtime tests passed
• 78 final core regression tests passed
• Ruff and git diff checks passed

The attempted full suite required additional optional dependencies and entered unrelated long-running campaign/platform failures; no Qoder-focused failures were observed.