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>

scripts/build-xcframework.sh

@@ -1,12 +1,12 @@
 #!/usr/bin/env bash
-# Build LumenCore.xcframework for the Apple clients — run ON A MAC with Xcode + rustup.
+# Build PunktfunkCore.xcframework for the Apple clients — run ON A MAC with Xcode + rustup.
 #
 #   rustup target add aarch64-apple-darwin x86_64-apple-darwin   # + aarch64-apple-ios for iOS
 #   bash scripts/build-xcframework.sh
 #
-# Output: clients/apple/LumenCore.xcframework (consumed by clients/apple/Package.swift).
-# The library is built WITH the `quic` feature (the lumen/1 connection API), so the bundled
-# header gets LUMEN_FEATURE_QUIC pre-defined — Swift sees lumen_connect & co. unconditionally.
+# Output: clients/apple/PunktfunkCore.xcframework (consumed by clients/apple/Package.swift).
+# The library is built WITH the `quic` feature (the punktfunk/1 connection API), so the bundled
+# header gets PUNKTFUNK_FEATURE_QUIC pre-defined — Swift sees punktfunk_connect & co. unconditionally.
 set -euo pipefail
 cd "$(dirname "$0")/.."
 
@@ -16,10 +16,10 @@ BUILD_IOS="${BUILD_IOS:-0}" # BUILD_IOS=1 adds an iOS slice (requires the ios ta
 # Deployment targets must match Package.swift's platforms, or every consumer link emits
 # "object file was built for newer macOS version" warnings.
 for t in "${TARGETS_MAC[@]}"; do
-    MACOSX_DEPLOYMENT_TARGET=14.0 cargo build --release -p lumen-core --features quic --target "$t"
+    MACOSX_DEPLOYMENT_TARGET=14.0 cargo build --release -p punktfunk-core --features quic --target "$t"
 done
 if [[ "$BUILD_IOS" == "1" ]]; then
-    IPHONEOS_DEPLOYMENT_TARGET=17.0 cargo build --release -p lumen-core --features quic --target aarch64-apple-ios
+    IPHONEOS_DEPLOYMENT_TARGET=17.0 cargo build --release -p punktfunk-core --features quic --target aarch64-apple-ios
 fi
 
 STAGE="$(mktemp -d)"
@@ -28,33 +28,33 @@ trap 'rm -rf "$STAGE"' EXIT
 # Universal macOS static lib.
 mkdir -p "$STAGE/macos"
 lipo -create \
-    target/aarch64-apple-darwin/release/liblumen_core.a \
-    target/x86_64-apple-darwin/release/liblumen_core.a \
-    -output "$STAGE/macos/liblumen_core.a"
+    target/aarch64-apple-darwin/release/libpunktfunk_core.a \
+    target/x86_64-apple-darwin/release/libpunktfunk_core.a \
+    -output "$STAGE/macos/libpunktfunk_core.a"
 
 # Headers dir: the generated C header (with the quic API force-enabled) + a modulemap so
-# Swift can `import LumenCore`.
+# Swift can `import PunktfunkCore`.
 mkdir -p "$STAGE/include"
 {
-    echo "#define LUMEN_FEATURE_QUIC 1"
-    cat include/lumen_core.h
-} > "$STAGE/include/lumen_core.h"
+    echo "#define PUNKTFUNK_FEATURE_QUIC 1"
+    cat include/punktfunk_core.h
+} > "$STAGE/include/punktfunk_core.h"
 cat > "$STAGE/include/module.modulemap" <<'EOF'
-module LumenCore {
-    header "lumen_core.h"
+module PunktfunkCore {
+    header "punktfunk_core.h"
     export *
 }
 EOF
 
-ARGS=(-library "$STAGE/macos/liblumen_core.a" -headers "$STAGE/include")
+ARGS=(-library "$STAGE/macos/libpunktfunk_core.a" -headers "$STAGE/include")
 if [[ "$BUILD_IOS" == "1" ]]; then
-    ARGS+=(-library target/aarch64-apple-ios/release/liblumen_core.a -headers "$STAGE/include")
+    ARGS+=(-library target/aarch64-apple-ios/release/libpunktfunk_core.a -headers "$STAGE/include")
 fi
 
 # Cargo does NOT fingerprint MACOSX_DEPLOYMENT_TARGET — units cached from a build without
 # it keep their old minos forever. Refuse to ship anything newer than the package floor
 # (objects BELOW it, e.g. rustup's precompiled std at 11.0, are fine and unavoidable).
-for obj in "$STAGE"/macos/liblumen_core.a; do
+for obj in "$STAGE"/macos/libpunktfunk_core.a; do
     bad=$(otool -l "$obj" 2>/dev/null | awk '/minos/ {print $2}' | sort -uV | awk -F. '$1 > 14' | head -1)
     if [[ -n "$bad" ]]; then
         echo "ERROR: $obj contains objects built for macOS $bad (> 14.0)." >&2
@@ -63,6 +63,6 @@ for obj in "$STAGE"/macos/liblumen_core.a; do
     fi
 done
 
-rm -rf clients/apple/LumenCore.xcframework
-xcodebuild -create-xcframework "${ARGS[@]}" -output clients/apple/LumenCore.xcframework
-echo "OK: clients/apple/LumenCore.xcframework"
+rm -rf clients/apple/PunktfunkCore.xcframework
+xcodebuild -create-xcframework "${ARGS[@]}" -output clients/apple/PunktfunkCore.xcframework
+echo "OK: clients/apple/PunktfunkCore.xcframework"