rename: lumen → punktfunk, everywhere

Full project rename, decided 2026-06-10:
- Crates/binaries: punktfunk-core / punktfunk-host / punktfunk-client-rs.
- C ABI: punktfunk_* symbols, Punktfunk* types, include/punktfunk_core.h,
  PUNKTFUNK_FEATURE_QUIC guard (header regenerated; cbindgen renames updated, incl.
  PUNKTFUNK_BTN_*/PUNKTFUNK_AXIS_* wire constants).
- Protocol: punktfunk/1 — control-plane magic LMN1 → PKF1, nonce salt lmn1 → pkf1.
  WIRE BREAK: clients must be rebuilt from this revision.
- Env knobs: PUNKTFUNK_VIDEO_SOURCE / PUNKTFUNK_COMPOSITOR / PUNKTFUNK_ZEROCOPY / ….
- Host config dir: ~/.config/punktfunk (the box's dir was migrated in place — the
  persistent identity is unchanged, pinned fingerprints stay valid).
- Swift package: PunktfunkKit + PunktfunkCore.xcframework + PunktfunkConnection
  (Sources/PunktfunkClient app + tests renamed with it); build-xcframework.sh updated.
- scripts/: 60-punktfunk.rules, punktfunk-host.service; OpenAPI doc regenerated.

Also: scripts/headless/run-headless-kde.sh — full headless Plasma bringup. Root cause of
"desktop but no apps/settings" over the stream: plasmashell launched without
XDG_MENU_PREFIX=plasma-, so the launcher resolved a nonexistent applications.menu and
rendered an empty menu. The script sets the complete KDE session env (menu prefix,
KDE_FULL_SESSION, session version) and rebuilds ksycoca before starting plasmashell.

Gate: 97/97 tests, clippy -D warnings (both feature sets), fmt, C-ABI harness PASS,
zero lumen references left outside .git.

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

docs/linux-setup.md

@@ -1,8 +1,8 @@
 # Linux host setup — NVIDIA GPU VM (M0/M2)
 
-How to bring up the build environment for the lumen Linux host on an NVIDIA-GPU Ubuntu VM
-and run the **M0** capture→encode spike. `lumen-core` already builds and is tested
-cross-platform; this is about the platform backends in `crates/lumen-host`.
+How to bring up the build environment for the punktfunk Linux host on an NVIDIA-GPU Ubuntu VM
+and run the **M0** capture→encode spike. `punktfunk-core` already builds and is tested
+cross-platform; this is about the platform backends in `crates/punktfunk-host`.
 
 > Target **Ubuntu 24.04 (noble)**: Sway 1.9, FFmpeg 6.1.1, xdg-desktop-portal 1.18.
 > 22.04 (jammy) ships Sway 1.7 / FFmpeg 4.4 — too old for this path; build from source or
@@ -11,7 +11,7 @@ cross-platform; this is about the platform backends in `crates/lumen-host`.
 ## 1. Bootstrap
 
 ```sh
-git clone git@git.unom.io:unom/lumen.git && cd lumen && git checkout m1-lumen-core
+git clone git@git.unom.io:unom/punktfunk.git && cd punktfunk && git checkout m1-punktfunk-core
 bash scripts/bootstrap-ubuntu.sh
 ```
 
@@ -68,11 +68,11 @@ bash scripts/headless/run-headless-sway.sh        # success logs "EGL vendor: NV
 
 # shell 2 — same user: set the client mode, import the portal env, write the env file
 bash scripts/headless/prepare-session.sh 2560x1440@60Hz
-source /tmp/lumen-sway-env.sh
+source /tmp/punktfunk-sway-env.sh
 swaymsg -t get_outputs                       # confirm HEADLESS-1 active
 swaymsg exec foot                            # optional: animated content to capture
 bash scripts/headless/capture-smoke-test.sh  # wf-recorder (wlr-screencopy) -> hevc_nvenc
-ffprobe /tmp/lumen-headless-test.mkv         # confirm a real H.265 stream
+ffprobe /tmp/punktfunk-headless-test.mkv         # confirm a real H.265 stream
 ```
 
 `wf-recorder` uses `wlr-screencopy` directly (no portal/D-Bus) — the fastest way to
@@ -89,26 +89,26 @@ The wlroots-on-NVIDIA env workarounds (`WLR_RENDERER=gles2`, `WLR_NO_HARDWARE_CU
 `GBM_BACKEND=nvidia-drm`, `sway --unsupported-gpu`, …) live in
 `scripts/headless/env.sh` — `source` it before launching anything Wayland.
 
-## 4. M0 proper — wire it into `lumen-core`
+## 4. M0 proper — wire it into `punktfunk-core`
 
 Goal (plan §8): headless output → PipeWire ScreenCast → NVENC → a playable file, then feed
-the encoded access units into a `lumen_core::Session` (host role). The module seams exist
-in `crates/lumen-host/src/{vdisplay,capture,encode,inject,pipeline}.rs`.
+the encoded access units into a `punktfunk_core::Session` (host role). The module seams exist
+in `crates/punktfunk-host/src/{vdisplay,capture,encode,inject,pipeline}.rs`.
 
-**Status: implemented and verified end-to-end** in `crates/lumen-host` (`m0.rs`,
+**Status: implemented and verified end-to-end** in `crates/punktfunk-host` (`m0.rs`,
 `capture/linux.rs`, `encode/linux.rs`). After the §3 bring-up:
 
 ```sh
-source /tmp/lumen-sway-env.sh
+source /tmp/punktfunk-sway-env.sh
 swaymsg exec foot   # animated content
 # Live portal capture → NVENC HEVC → playable file, with each AU also round-tripped
-# through a lumen_core host→client Session (FEC + packetize + reassemble) and verified:
-cargo run -p lumen-host -- m0 --source portal --seconds 5 --out /tmp/lumen-m0.h265
-ffprobe /tmp/lumen-m0.h265
+# through a punktfunk_core host→client Session (FEC + packetize + reassemble) and verified:
+cargo run -p punktfunk-host -- m0 --source portal --seconds 5 --out /tmp/punktfunk-m0.h265
+ffprobe /tmp/punktfunk-m0.h265
 # No capture session needed (encode + core only): --source synthetic
 ```
 
-Verified result: `1920x1080` HEVC, ~300 frames in 5s, `lumen-core loopback … 0 mismatches`.
+Verified result: `1920x1080` HEVC, ~300 frames in 5s, `punktfunk-core loopback … 0 mismatches`.
 The portal negotiates packed **`RGB` (24-bit, 3 bpp)** on wlroots; the encoder expands it to
 `rgb0` (one pad byte/pixel, no colour math) since NVENC accepts `rgb0`/`bgr0` but not
 `rgb24`. dmabuf zero-copy import is still deferred (plan §9) — this is the CPU-copy path.