docs: user-facing docs revamp — structured product docs + per-platform setup

Replace the dev/agent-log pages with a proper user-facing doc set:

- Getting Started: Introduction (rewritten), How It Works, Quick Start.
- Host Setup: Requirements, then clean per-platform guides — Ubuntu GNOME,
  Ubuntu KDE, Fedora KDE (new), Bazzite (rewritten) — plus Running as a Service
  (desktop / headless GNOME / headless KDE).
- Connecting: Clients overview, Moonlight, Pairing & Trust.
- Configuration: host.env reference, Host CLI, Troubleshooting.
- The dev/design notes (architecture, roadmap, the deferred design specs, CI)
  move to a clearly-separated "Project & Internals" nav section.

Removes the superseded box-specific pages (gnome-box, headless-box, linux-setup,
overview). status.md (the internal progress tracker, with box IPs) is kept as a
file but dropped from the public nav. Site builds clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

docs-site/content/docs/how-it-works.md

@@ -0,0 +1,61 @@
+---
+title: How It Works
+description: The ideas behind punktfunk — per-client virtual displays, the two protocols, and trust.
+---
+
+You don't need to know any of this to use punktfunk, but it helps to understand what's happening
+when you connect.
+
+## A virtual display, sized to your device
+
+When a client connects, the host asks your desktop to create a **new virtual display** at exactly the
+client's resolution and refresh rate, captures that display, and streams it. The virtual display is
+real to your desktop — apps can be moved onto it, games open on it — but it isn't tied to any physical
+monitor. When the client disconnects, the virtual display goes away.
+
+That's why a 1080p60 laptop and a 1440p120 desktop can stream from the same host **at the same time**,
+each at its own mode — they each get their own virtual display.
+
+How the virtual display is created depends on your desktop:
+
+| Desktop | How |
+|---|---|
+| **GNOME** (Mutter) | A virtual monitor via the screen-cast API |
+| **KDE Plasma** (KWin) | A virtual output via KWin's screencast |
+| **Bazzite / Steam** (gamescope) | A nested gamescope session launched at the client's mode |
+| **Sway** (wlroots) | A headless output added to the running session |
+
+## From screen to GPU to wire
+
+Captured frames never touch the CPU on their way to the encoder. They go straight from the
+compositor to the GPU's NVENC hardware encoder (HEVC/H.264/AV1) and out to the network — a **zero-copy
+GPU path** that keeps latency low even at high resolutions and frame rates.
+
+## Two protocols
+
+punktfunk speaks two protocols over the same host:
+
+- **GameStream** — the protocol Moonlight uses. Any [Moonlight](/docs/moonlight) client connects with
+  no special software. This is the most compatible way in.
+- **punktfunk/1 (native)** — a purpose-built protocol with a QUIC control channel and a UDP data
+  channel hardened with forward error correction and encryption. It's lower-latency and more resilient
+  on imperfect networks, and it's what the [Apple app](/docs/clients) uses.
+
+Both run from a single host process, so you don't choose up front — Moonlight clients use GameStream,
+the native clients use punktfunk/1.
+
+## Pairing and trust
+
+The first time a device connects, you pair it: the host shows a short **PIN**, you type it into the
+client, and the two remember each other. After that the device reconnects automatically on a pinned
+cryptographic identity — no PIN, no account, no cloud. See [Pairing & Trust](/docs/pairing).
+
+## Finding hosts
+
+Hosts advertise themselves on your local network, so clients can **discover** them automatically
+instead of needing an IP address. The Apple app and Moonlight both list hosts they find on the LAN.
+
+## Multiple devices at once
+
+A host can stream to several clients simultaneously — your laptop and your TV both viewing (and
+controlling) the desktop, each at its own resolution. See [Multiple devices](/docs/configuration#multiple-devices).