docs: repo-wide housekeeping — sync README & docs with the code as shipped

Six parallel audits swept the root docs, docs-site, every per-directory
README, and the packaging docs; every claim below was verified against
the source before editing.

- README: Layout gains the six missing crates (pf-client-core,
  pf-presenter, pf-console-ui, pf-ffvk, pf-driver-proto, punktfunk-tray),
  clients/session, api/ and ci/; Linux/Windows client rows reflect the
  shell + Vulkan-session split and the Vulkan Video -> VAAPI/D3D11VA ->
  software decode chains; the "every client over a C ABI" claim is
  corrected (Rust clients link the core directly); tiered stats overlay
  + console shell noted; Apple row mentions AV1.
- CONTRIBUTING: drop the dead CLAUDE.md link (deliberately untracked);
  point at the README's build/invariants sections. SECURITY: 0.9.0.
- host-cli/pairing: --allow-pairing/--require-pairing are no-op legacy
  names — pairing is required by default, --allow-tofu is the real flag;
  document --data-port and --idle-timeout-ms.
- configuration: document PUNKTFUNK_RECOVER_SESSION_CMD (session-crash
  recovery hook), PUNKTFUNK_MDNS, PUNKTFUNK_DATA_PORT.
- virtual-displays/gnome: GNOME per-client scaling shipped (host-
  persisted) — flip the ❌ to ✅ and describe how it works.
- stats: new "Detail levels" section (Off/Compact/Normal/Detailed +
  per-platform cycle gestures); retire the GTK hand-off note.
- clients/install-client/status/roadmap: decode chains, Windows client
  validation narrowed to HDR-only pending, adaptive bitrate, console
  shell, Apple AV1, Windows host vendor list.
- Sub-READMEs: clients/linux rewritten for the re-architecture; session
  Windows decode rung + d3d11va knob; Windows tiered overlay; Android
  minSdk 28; decky file table; host zerocopy/ path; scripts port
  47992 and steamos-host.md; pf-dualsense source path.
- packaging: canary version bases are tag-derived (<next-minor> via
  pf-version.sh/.ps1), codecs-extra not ffmpeg-full, document the
  pinned offline-Skia tarball + SKIA_BINARIES_URL and vulkan-headers.
- Convert 15 dangling design/*.md links to the punktfunk-planning
  prose convention (those docs live in the private planning repo).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

docs-site/content/docs/configuration.md

@@ -75,6 +75,12 @@ See your desktop page ([KDE](/docs/kde), [GNOME](/docs/gnome)) for when to set t
 | `PUNKTFUNK_KWIN_VIRTUAL_PRIMARY` | `1` | Make the streamed per-session output the sole desktop so plasmashell + windows render on it (not on the headless bootstrap output). Set by the KDE appliance `host.env`. Superseded by the console's **Topology** setting. |
 | `PUNKTFUNK_MUTTER_VIRTUAL_PRIMARY` | `1` | GNOME/Mutter equivalent of the above. |
 
+## Session recovery (Linux)
+
+| Setting | Values | Meaning |
+|---|---|---|
+| `PUNKTFUNK_RECOVER_SESSION_CMD` | command | Operator hook fired (debounced) when a client connects while **no graphical session is live** for the host's user — the state a compositor crash leaves behind (gnome-shell SIGSEGV → GDM greeter, whose auto-login is once-per-boot). Typically `sudo -n systemctl restart gdm` with a matching NOPASSWD sudoers rule, or `systemctl restart display-manager` under a polkit rule; with auto-login enabled the restart brings the desktop back and the client's automatic retry lands in it. Unset/empty = disabled (the default). |
+
 ## Video quality
 
 | Setting | Values | Meaning |
@@ -110,6 +116,13 @@ See your desktop page ([KDE](/docs/kde), [GNOME](/docs/gnome)) for when to set t
 | `PUNKTFUNK_RENDER_ADAPTER` | description substring | Multi-GPU boxes only: force the NVENC/capture GPU by adapter Description substring (e.g. `4090`). Leave unset on single-GPU machines. |
 | `PUNKTFUNK_HOST_CMD` | e.g. `serve --gamestream` | The host subcommand the service launches. Default `serve --gamestream`; use `serve` for a secure native-only host. |
 
+## Network & discovery
+
+| Setting | Values | Meaning |
+|---|---|---|
+| `PUNKTFUNK_MDNS` | `1` · `0` *(default on)* | mDNS adverts (native + GameStream). `0` skips them (same as `--no-mdns`) — for networks/containers where multicast doesn't work; add the host by address in the client instead. |
+| `PUNKTFUNK_DATA_PORT` | port | Pin the per-session video data plane to a fixed UDP port and stream direct (no hole-punch) — open exactly that port in the host firewall. Same as `serve --data-port`; see [Troubleshooting](/docs/troubleshooting). Default: random port + hole-punch. |
+
 ## Auth, API & paths
 
 | Setting | Values | Meaning |