revert: computer-use cua-driver (PR #16919) (#16927)

Reverts PR #16919 (commits dad10a78d, 413ee1a28, b4a8031b2, afb958829)
which was merged prematurely. Restoring the pre-merge state so #14817
and #15328 can be revisited as standing PRs.

Reverted commits:
- afb958829 fix(computer-use): harden image-rejection fallback + AUTHOR_MAP
- b4a8031b2 fix(computer-use): unwrap _multimodal tool results
- 413ee1a28 feat(computer-use): background focus-safe backend
- dad10a78d feat(computer-use): cua-driver backend, universal any-model schema

Co-authored-by: teknium1 <teknium@users.noreply.github.com>

website/docs/reference/tools-reference.md

@@ -92,13 +92,6 @@ Scoped to the Feishu document-comment handler. Drives comment read/write operati
 | `ha_list_entities` | List Home Assistant entities. Optionally filter by domain (light, switch, climate, sensor, binary_sensor, cover, fan, etc.) or by area name (living room, kitchen, bedroom, etc.). | — |
 | `ha_list_services` | List available Home Assistant services (actions) for device control. Shows what actions can be performed on each device type and what parameters they accept. Use this to discover how to control devices found via ha_list_entities. | — |
 
-## `computer_use` toolset
-
-| Tool | Description | Requires environment |
-|------|-------------|----------------------|
-| `computer_use` | Background macOS desktop control via cua-driver — screenshots (SOM / vision / AX), click / drag / scroll / type / key / wait, list_apps, focus_app. Does NOT steal the user's cursor or keyboard focus. Works with any tool-capable model. macOS only. | `cua-driver` on `$PATH` (install via `hermes tools`). |
-
-
 :::note
 **Honcho tools** (`honcho_profile`, `honcho_search`, `honcho_context`, `honcho_reasoning`, `honcho_conclude`) are no longer built-in. They are available via the Honcho memory provider plugin at `plugins/memory/honcho/`. See [Memory Providers](../user-guide/features/memory-providers.md) for installation and usage.
 :::