[codex] Add AGY debugger provider and tmux mouse defaults

[bookandlover]

Summary

• Add an agy provider backend for pane-backed debugger sessions, including manifest, launcher, and session binding support.
• Register AGY in the provider registry, start command resolution, session pathing, and zombie cleanup paths.
• Enable project-namespace tmux interactive defaults (mouse on, vi copy-mode keys, larger history) so four-pane CCB sessions support mouse pane selection and scrollback after startup.
• Cover AGY catalog/runtime behavior plus tmux namespace policy defaults with regression tests.

Why

The debugger role should launch through Google Antigravity CLI (agy) instead of reusing the Gemini provider. AGY also needs a first-class provider entry so CCB can validate debugger:agy layouts and start the debugger pane consistently.

The updated project namespace path starts tmux with -f /dev/null, so it does not inherit config/tmux-ccb.conf. Without explicitly applying interactive defaults, the new four-pane session starts with mouse off and mode-keys emacs, forcing users to switch panes with prefix o and preventing normal mouse scrollback.

Google Antigravity CLI docs note that launch flags can override settings, including --dangerously-skip-permissions: https://antigravity.google/docs/cli-using

Validation

• uvx pytest test/test_v2_project_namespace_backend.py test/test_v2_project_namespace_state.py test/test_v2_tmux_start_layout.py test/test_v2_provider_core_registry.py test/test_v2_provider_catalog.py test/test_v2_runtime_launch.py -q -> 109 passed in 17.10s
• python3 -m compileall -q lib ccb bin -> exit 0
• Current project tmux options after hotfix: mouse on, mode-keys vi, history-limit 50000

Notes

This PR adds pane-backed startup/session support for AGY. It does not add a full provider execution adapter, so protocol-level ccb ask debugger support can be handled separately if maintainers want AGY ask completion semantics beyond visible tmux pane startup.

[SeemSeam]

mouse bug 已经修复了 ，我考虑下新provider