Add headless streaming mode + Mac client + full docs

Headless mode (new) — for KVM-attached hosts streaming to disconnected clients
- --headless / --mirror flags; default headless on hostname JARVIS, mirror elsewhere
- New lib/headless.sh installs prep-cmd hooks to ~/.local/share/omarchy-moonlight/bin
- bin/sunshine-stream-do.sh creates/resizes a Hyprland HEADLESS-1 output to the
  connecting client's resolution and migrates the active workspace onto it
- bin/sunshine-stream-undo.sh tears down the headless output on disconnect and
  returns the workspace to a non-headless monitor when one is available
- lib/config.sh writes capture=wlr, output_name=HEADLESS-1, and the JSON
  global_prep_cmd entry referencing the installed hook paths
- lib/preflight.sh adds a preflight_headless step that checks hyprctl, jq, and
  a running Hyprland session (warn-only, install can proceed)
- lib/verify.sh adds checks for the hook scripts and the wlr/global_prep_cmd
  config lines

Mac client
- client/install-macos.sh: Darwin guard, Homebrew presence check, brew cask
  install of Moonlight, idempotent
- client/README.md: per-platform install (macOS / Android / iOS / Apple TV /
  Linux + Steam Deck) and the five-step first-pair walkthrough

Other
- jq added to the helper install set in lib/packages.sh (hooks parse Hyprland
  JSON output)
- README.md rewritten to cover both modes, the new flags, the tuned defaults
  per mode + per vendor, the headless internals, and the client pointer

client/README.md

@@ -0,0 +1,125 @@
+# Moonlight clients
+
+This directory covers installing Moonlight on the devices that connect to your
+Sunshine host. The host side (Sunshine on Linux) is documented in the
+[top-level README](../README.md).
+
+## Install
+
+### macOS
+
+From a Mac that has this repo checked out:
+
+```sh
+./client/install-macos.sh
+```
+
+The script verifies Homebrew is present and runs `brew install --cask moonlight`.
+It will not install Homebrew for you.
+
+Manual equivalent:
+
+```sh
+brew install --cask moonlight
+```
+
+Fallback (no Homebrew): download a signed DMG from the official releases page
+and drag `Moonlight.app` into `/Applications`:
+
+- https://github.com/moonlight-stream/moonlight-qt/releases
+
+### Android
+
+Install "Moonlight Game Streaming" from the Play Store:
+
+- https://play.google.com/store/apps/details?id=com.limelight
+
+### iOS / iPadOS
+
+Install "Moonlight Game Streaming" from the App Store:
+
+- https://apps.apple.com/us/app/moonlight-game-streaming/id1000551566
+
+### Apple TV
+
+Same listing on the tvOS App Store. Search "Moonlight Game Streaming" on the
+Apple TV itself, or use the App Store link above from an iOS device signed in
+to the same Apple ID.
+
+### Steam Deck / Linux
+
+Use `moonlight-qt` from your distro's package manager (Flatpak on Steam Deck,
+`pacman`/`apt` elsewhere). It is the same Qt-based client as macOS and Windows.
+
+## First pair
+
+The pairing flow is the same on every client.
+
+1. Confirm the host is healthy. On the host machine:
+
+   ```sh
+   ./install.sh --doctor
+   ```
+
+   Sunshine must be running and reachable on the LAN.
+
+2. On the client, open Moonlight. The host should appear automatically via
+   mDNS as long as the client is on the same LAN. If it does not appear, use
+   "Add Host Manually" and enter the host's LAN IP address.
+
+3. Click or tap the host. Moonlight displays a 4-digit PIN.
+
+4. On the host machine, open the Sunshine web UI:
+
+   ```
+   https://localhost:47990
+   ```
+
+   Accept the self-signed certificate. Log in (credentials are set the first
+   time you visit). Go to the PIN tab, enter the 4-digit PIN from the client,
+   and submit. Pairing typically completes within about 5 seconds.
+
+5. Back in Moonlight, the host now shows as "Paired". Click it to see the
+   available apps. The default app is "Desktop", which is either a full-screen
+   mirror of the host's display or a headless virtual display, depending on
+   how the host is configured.
+
+## Streaming notes
+
+- **Resolution.** Moonlight lets you pick a target stream resolution per host.
+  On a headless-configured host, that resolution is what the host actually
+  renders at. On a mirror-configured host, the host renders at its native
+  resolution and Moonlight downscales on the client.
+
+- **Bitrate.** Moonlight's defaults are conservative for general internet use.
+  For LAN streaming, bump it to 50-100 Mbps.
+
+- **Audio.** By default, Moonlight captures audio from the host and plays it
+  on the client. If you want the host's speakers/monitor to keep playing
+  audio while you stream, enable "Play audio on host" in Moonlight's stream
+  settings.
+
+## Troubleshooting
+
+- **"Host not found" / host does not appear automatically.** Confirm both
+  machines are on the same LAN/VLAN. mDNS does not traverse VLANs without an
+  mDNS reflector. Fall back to "Add Host Manually" with the host's IP.
+
+- **Pairing PIN does not work.** Two common causes: the Sunshine web UI
+  session has timed out (log in again and re-enter the PIN), or the PIN is
+  being entered into the wrong host (multiple Sunshine instances on the LAN).
+  Cancel and re-trigger pair from the client to get a fresh PIN.
+
+- **Black screen after pairing.** This is a host-side problem. On the host:
+
+  ```sh
+  ./install.sh --doctor
+  ```
+
+- **Mac cannot reach `brew`.** Homebrew is not installed (or not on `PATH`).
+  Install it per https://brew.sh, open a fresh shell, then re-run
+  `./client/install-macos.sh`.
+
+- **Android sees the host but cannot connect.** The Android device is
+  probably on a guest WiFi SSID that is isolated from the main LAN. Move it
+  to the main LAN, or use "Add Host Manually" with the host IP.