logiguard fork: GPUI xdg-activation keyboard-focus serial fix

Single-commit orphan branch: full zed-industries/zed @ 8c74db0 source tree
with a 3-file patch applied (no upstream history).

Patch (crates/gpui_linux/src/linux/wayland/):
  - serial.rs: add SerialKind::KeyboardEnter
  - client.rs: store wl_keyboard.enter serial; add latest_serial_of()
  - window.rs: activate() uses keyboard-enter serial (Mutter focus gate)

Mutter honors window activation only when the token carries the keyboard-
focus serial from wl_keyboard.enter; GPUI used a stale mouse-press serial.
See docs/tray-window-focus-wayland.md in logiguard.

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

nix/livekit-libwebrtc/libwebrtc.version

@@ -0,0 +1,22 @@
+/* Linker version script for libwebrtc.so (Linux only).
+ *
+ * When libwebrtc.so is built with rtc_use_pipewire=true and
+ * -fvisibility=default, PipeWire lazy-load trampoline stubs (pw_*, spa_*)
+ * are exported as weak symbols. If the PipeWire ALSA plugin
+ * (libasound_module_pcm_pipewire.so) is later dlopen'd by libasound,
+ * the dynamic linker may resolve the plugin's pw_* references through
+ * libwebrtc.so's broken trampolines instead of the real libpipewire.so,
+ * causing a SIGSEGV (NULL function pointer dereference).
+ *
+ * This script hides only those third-party symbol namespaces while
+ * keeping every WebRTC / BoringSSL / internal symbol exported (which
+ * the Rust webrtc-sys bindings require).
+ */
+{
+  global:
+    *;
+
+  local:
+    pw_*;
+    spa_*;
+};