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>

crates/collab/src/api.rs

@@ -0,0 +1,74 @@
+pub mod events;
+pub mod extensions;
+
+use crate::Result;
+use axum::{headers::Header, http::HeaderName};
+use std::sync::OnceLock;
+
+pub use extensions::fetch_extensions_from_blob_store_periodically;
+
+pub struct CloudflareIpCountryHeader(String);
+
+impl Header for CloudflareIpCountryHeader {
+    fn name() -> &'static HeaderName {
+        static CLOUDFLARE_IP_COUNTRY_HEADER: OnceLock<HeaderName> = OnceLock::new();
+        CLOUDFLARE_IP_COUNTRY_HEADER.get_or_init(|| HeaderName::from_static("cf-ipcountry"))
+    }
+
+    fn decode<'i, I>(values: &mut I) -> Result<Self, axum::headers::Error>
+    where
+        Self: Sized,
+        I: Iterator<Item = &'i axum::http::HeaderValue>,
+    {
+        let country_code = values
+            .next()
+            .ok_or_else(axum::headers::Error::invalid)?
+            .to_str()
+            .map_err(|_| axum::headers::Error::invalid())?;
+
+        Ok(Self(country_code.to_string()))
+    }
+
+    fn encode<E: Extend<axum::http::HeaderValue>>(&self, _values: &mut E) {
+        unimplemented!()
+    }
+}
+
+impl std::fmt::Display for CloudflareIpCountryHeader {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}
+
+pub struct SystemIdHeader(String);
+
+impl Header for SystemIdHeader {
+    fn name() -> &'static HeaderName {
+        static SYSTEM_ID_HEADER: OnceLock<HeaderName> = OnceLock::new();
+        SYSTEM_ID_HEADER.get_or_init(|| HeaderName::from_static("x-zed-system-id"))
+    }
+
+    fn decode<'i, I>(values: &mut I) -> Result<Self, axum::headers::Error>
+    where
+        Self: Sized,
+        I: Iterator<Item = &'i axum::http::HeaderValue>,
+    {
+        let system_id = values
+            .next()
+            .ok_or_else(axum::headers::Error::invalid)?
+            .to_str()
+            .map_err(|_| axum::headers::Error::invalid())?;
+
+        Ok(Self(system_id.to_string()))
+    }
+
+    fn encode<E: Extend<axum::http::HeaderValue>>(&self, _values: &mut E) {
+        unimplemented!()
+    }
+}
+
+impl std::fmt::Display for SystemIdHeader {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}", self.0)
+    }
+}