[codex] Add Pathfinder dialog outcomes

[trek-e]

Summary

• add a typed Pathfinder player dialog outcome vocabulary for renderable text vs explicit suppressed responses
• route dialog answer consumption and player cancel handling through dialog outcomes instead of blank-string suppression
• keep legacy dialog text wrappers for direct callers while documenting the new outcome contract
• update dialog/router/player adapter tests to cover the explicit suppressed response path

Validation

• uv run ruff check CONTEXT.md interfaces/discord/pathfinder_player_dialog_outcome.py interfaces/discord/pathfinder_player_dialog.py interfaces/discord/dialog_router.py interfaces/discord/discord_router_bridge.py interfaces/discord/pathfinder_player_adapter.py interfaces/discord/response_renderer.py interfaces/discord/tests/test_dialog_router.py interfaces/discord/tests/test_phase38_integration.py
• cd interfaces/discord && uv run pytest tests/test_dialog_router.py tests/test_phase38_integration.py tests/test_pathfinder_player_dialog.py tests/test_response_renderer.py
• cd interfaces/discord && uv run pytest tests/test_pathfinder_player_adapter.py
• cd interfaces/discord && uv run pytest

Notes

• no uv.lock files changed in this branch