Establish logical sessions and durable recovery plan history

[heznpc]

Establish the current development baseline on main with five commits covering logical session identity and recovery plans.

• Group Codex rollout fragments by provider session identity and inspect all fragments of a logical session.
• Preserve user recovery goals with checked byte accounting and distinguish target occupancy reduction from signed volume free-space change.
• Persist a bounded, display-only recovery journal with durable checkpoints and interruption handling. Historical records contain no execution tokens and cannot resume approval.
• Bound preview subprocesses and exercise the recovery lifecycle through the real cleanup client in isolated fixtures.

Validation:

• All 513 Mac Swift tests pass locally with warnings as errors and complete strict-concurrency checking.
• The isolated live recovery harness passes through the real shell, pinned-FD transport, preview, execution, receipt, durable journal, and restart without executable approval state.
• The existing source launcher builds and launches the native app; the Work list and persisted recovery-plan journal were inspected in the running UI.
• Full main-targeted GitHub CI passed for the exact five-commit head: Linux validation, Python 3.9 source CLI, macOS Python, Windows PowerShell, iOS Swift, and macOS Swift including the Universal 2 DMG build/audit. CodeQL passed as well.

Project/asset domain modeling is a subsequent design step and is outside this baseline PR.