feat: PyroWave Phase 3 — pinned rate, all-intra silencing, opt-in UI, notices, docs

plan §4.6 + Phase 3 productization:

- Pinned bitrate: an Automatic client (bitrate 0) on a PyroWave session
  resolves to the codec's ~1.6 bpp operating point for the mode (≈200
  Mbps at 1080p60) instead of the 20 Mbps H.26x default; explicit rates
  are honored. Mid-stream SetBitrate retargets are refused with the
  pinned rate acked (guards old/foreign clients), and the client-side
  AIMD controller + startup capacity probe stay off for the codec — no
  rate descent into wavelet mush, no climb probe whose VBV reasoning
  doesn't apply to hard per-frame CBR. Unit-tested.

- All-intra silencing: the data plane drops drained keyframe/RFI
  requests on PyroWave sessions (the next frame IS the recovery), so
  the forced-IDR cooldown, RFI attempt, and storm coalescing never run.

- Opt-in UI: 'PyroWave (wired LAN)' joins the console's Video-codec
  cycler; trust::Settings maps it to CODEC_PYROWAVE. Safe everywhere by
  the negotiation contract — an un-advertised preference falls back
  through the ladder.

- FEC: decision recorded — adaptive FEC (10% start, loss-report driven)
  stays as-is for the MVP opaque-AU mode; the FEC≈0 policy belongs to
  the Phase-4 datagram-aligned mode.

- THIRD-PARTY-NOTICES: the generator now lists third-party trees
  vendored inside first-party crates (pyrowave, Granite subset, volk,
  Vulkan-Headers) with their full license texts; file regenerated.

- docs-site: 'PyroWave (wired-LAN codec)' page — what it is, the
  bandwidth table, how to enable it, current limits.

Validated on .21: 309 host + 148 core + 26 client tests green,
console-ui clean, both feature configs.

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

docs-site/content/docs/meta.json

@@ -24,6 +24,7 @@
     "sway",
     "running-as-a-service",
     "virtual-displays",
+    "pyrowave",
     "host-cli",
     "---Connecting---",
     "clients",

docs-site/content/docs/pyrowave.md

@@ -0,0 +1,65 @@
+---
+title: PyroWave (wired-LAN codec)
+description: The opt-in ultra-low-latency wavelet codec for wired links — what it is, the bandwidth it needs, and how to turn it on.
+---
+
+PyroWave is an **opt-in** video codec mode for links that can afford real bandwidth: wired
+Ethernet, a docked Steam Deck, a 2.5GbE LAN. It trades bitrate for latency — instead of
+H.264/HEVC/AV1 on the GPU's video engine, frames are compressed with
+[PyroWave](https://github.com/Themaister/pyrowave), an intra-only wavelet codec running as plain
+Vulkan compute. Punktfunk vendors a pinned copy and runs it on both ends.
+
+**It is never selected automatically.** HEVC/AV1 remain the codecs for Wi-Fi and everything
+else; PyroWave engages only when *you* pick it on the client **and** the host supports it. If
+either side can't, the session silently falls back to the normal codec ladder.
+
+## Why you'd want it
+
+- **Codec latency drops by an order of magnitude.** Encode and decode each take a fraction of a
+  millisecond of GPU compute (measured ~0.15 ms encode / ~0.07 ms decode at 1080p on an
+  RTX 5070 Ti), versus one-to-several milliseconds per side for the hardware H.26x pipelines.
+- **Every frame is a keyframe.** There is no GOP, no reference chain, no keyframe round-trip
+  after packet loss — a lost frame costs exactly that frame, and the next one is already a
+  complete picture. The whole IDR/recovery apparatus that produces loss-time stutter simply
+  doesn't exist in this mode.
+- **Uniform frame sizes.** The rate control hits its per-frame byte budget exactly, so the
+  pacer sees a flat load instead of 20–40× keyframe spikes.
+
+## What it costs
+
+Bandwidth. At the codec's ~1.6 bits-per-pixel operating point (4:2:0, 60 fps):
+
+| Mode | Bitrate |
+|---|---|
+| 1280×800 @ 60 (Deck) | ≈ 100 Mbps |
+| 1920×1080 @ 60 | ≈ 200 Mbps |
+| 2560×1440 @ 60 | ≈ 355 Mbps |
+| 3840×2160 @ 60 | ≈ 800 Mbps |
+
+120 Hz doubles these. Gigabit Ethernet tops out around 940 Mbps of payload, so 4K60 wants
+2.5GbE (or a lower rate). **Do not run this over Wi-Fi** — that's what HEVC/AV1 are for.
+
+Also: PyroWave is **8-bit SDR only**. An HDR session stays on HEVC/AV1 regardless of this
+setting.
+
+## Turning it on
+
+1. **Host** (Linux): build/install a host with the `pyrowave` feature. On an NVIDIA host the
+   capture path additionally needs `PUNKTFUNK_ENCODER=pyrowave` in `host.env` for the codec to
+   be advertised; AMD/Intel hosts advertise it automatically when the feature is present.
+2. **Client** (Linux session client with the `pyrowave` feature): set **Settings → Video
+   codec → PyroWave (wired LAN)** in the gamepad console, or launch with
+   `PUNKTFUNK_PREFER_PYROWAVE=1`.
+3. Leave the bitrate on Automatic: a PyroWave session pins itself to the ~1.6 bpp rate for
+   your mode (≈200 Mbps at 1080p60). An explicit bitrate is honored if you set one, but the
+   adaptive-bitrate controller stays off either way — this codec has no useful low-rate
+   regime, so under sustained loss the right move is switching back to HEVC, not degrading.
+
+The stats overlay shows `pyrowave` as the decode path when the mode is active.
+
+## Current limits
+
+- Linux host + Linux client (including docked Deck) today; the Windows host and the Apple
+  native port are tracked on the [roadmap](/docs/roadmap).
+- 8-bit SDR, 4:2:0 only.
+- Mid-stream resolution changes rebuild the stream rather than switching seamlessly.