docs: add Mac-on-Linux acceptance matrix for workstation-v0

[Copilot]

The workstation-v0 Mac-on-Linux lane had no single reference tracking what is implemented, validated, planned, or explicitly out-of-scope — making it hard for reviewers and agents to assess coverage.

Added

docs/workstation/mac-on-linux-acceptance.md — acceptance matrix with four status tiers (implemented, validation-backed, planned, non-goal) across all Mac-on-Linux feature areas:

• Launcher/palette — Super+Space → sourceos palette, fuzzel, Lampstand action bus
• Files/Terminal shortcuts — Super+E / Super+Return bindings, doctor-validated
• Screenshots — all four Super+Shift+{3-6} bindings, mac-screenshot.sh wrapper, check-mac-polish.sh validation
• Quick Look/Sushi — Sushi install + binary check; spacebar-to-preview marked non-goal (requires Nautilus extension)
• Sidebar bookmarks — files-sidebar.sh + installer hook
• Appearance defaults — appearance-apply.sh settings, left window controls, hot-corners-off, 12h clock; proprietary themes marked non-goal
• Keyboard/remap policy — input-remapper primary, xremap template, Kinto compat lane; xremap/Kinto auto-install marked non-goal
• Gestures/Fusuma — fusuma-apply.sh, user service; libinput CI smoke marked planned
• Lampstand search — sourceos-search.sh, install script, unit check
• Doctor/status validation — doctor.sh, sourceos status --json, aggregate polish check, contract test; full macOS parity marked non-goal

Each row links directly to the relevant script/helper path.

[mdheller]

Replay review:

This PR should become part of the fresh workstation acceptance cleanup branch, not merge from its current non-mergeable branch.

Preserve as canonical content:

• the four-state matrix (implemented, validation-backed, planned, non-goal);
• the separation between Mac-like GNOME workstation v0 and full macOS parity;
• links from each feature row to concrete helper/script paths;
• explicit non-goals for full macOS parity.

Recommended action: replay the acceptance matrix onto current main, update it to reflect any work already landed since this PR was opened, then close this stale PR as superseded.