Show enhancement availability in terminal and desktop interfaces

## Problem

Users cannot currently see whether AI-enhanced suggestions are available for the active set. Offering the control for an unenhanced set would imply that the feature is active when no compatible enrichment exists.

## Proposed change

Render shared enhancement availability consistently in the TUI, plain-watch output, and PySide6/QML desktop interface.

When available, identify the active profile as AI-enhanced and provide the enable/disable control. When unavailable, show a concise set-specific message and disable or omit the control.

Make clear that the profile was enhanced offline; no model is called during the live draft.

Keep all availability and command behavior in the shared session. Frontends remain presentation adapters.

## Acceptance Criteria

- [ ] AC1: `tests/test_tui.py` verifies available, enabled, disabled, and unavailable enhancement states and user commands.
- [ ] AC2: `tests/test_watch.py` verifies that plain-watch output identifies enhanced suggestions when active and does not claim enhancement for unenhanced sets.
- [ ] AC3: `tests/test_qt_adapter.py` verifies immutable session-state translation and enable/disable command dispatch.
- [ ] AC4: `tests/test_qt_gui.py` verifies that the desktop control is available only for enhanced profiles and that unavailable copy includes the active set.
- [ ] AC5: TUI and desktop wording states that enrichment is profile-backed and does not imply live AI processing.
- [ ] AC6: The actual terminal and desktop workflows are visually exercised with enhanced and unenhanced mock profiles.
- [ ] AC7: Core and session modules remain free of Textual, PySide6, QML, and presentation-specific dependencies.

## Dependencies

- Expose enhancement availability through the live session.

## Implementation classification

- **Estimated size:** M
- **Orchestration risk:** High
- **Reason:** The same availability contract must remain consistent across terminal and desktop surfaces.

Start with the shared live session and the interfaces named in the issue, then read tests/test_tui.py, tests/test_watch.py, tests/test_qt_adapter.py, and tests/test_qt_gui.py. Verify the availability states and command dispatch in those tests, then visually exercise enhanced and unenhanced mock profiles as described in the acceptance criteria.

Written by the indexing model from the issue text.