fix: find cce binaries under systemd's PATH

The image context menu never once opened on the real desktop. It shells
out to ccectl and cce-cloud by bare name, and this process runs as a
systemd user service whose PATH is /usr/local/bin:/usr/bin — ~/.local/bin,
where every cce binary is installed, is not on it. The first spawn failed
with ENOENT and the menu silently gave up.

It worked in every test because the test harness spawned cce-grid from
the compositor, which inherits the full session PATH. The environment
that matters was the one never exercised.

de_bin() resolves a cce binary beside the running executable, falling
back to PATH for a dev build run out of target/. Also fixes drop-failure
notifications, which went through the same dead ccectl call.

Verified in the failure regime this time: a shadow client launched with
PATH=/usr/local/bin:/usr/bin at scale 2 opens the menu and completes the
removal.

Co-Authored-By: Claude Opus 5 <[email protected]>

 src/items.rs | 28 +++++++++++++++++++++++++---
 1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/src/items.rs b/src/items.rs
index 48bee0c..0a5f424 100644
--- a/src/items.rs
+++ b/src/items.rs
@@ -315,6 +315,28 @@ pub fn save_to_desktop(bytes: &[u8], name: &str) -> std::io::Result<PathBuf> {
     Ok(path)
 }
 
+/// Resolve a cce binary that is installed beside this one.
+///
+/// This process runs as a systemd user service, whose PATH is
+/// `/usr/local/bin:/usr/bin` — `~/.local/bin`, where every cce binary is
+/// installed, is NOT on it. Spawning one by bare name therefore fails with
+/// ENOENT under systemd while working perfectly from a shell or when the
+/// compositor spawns it, which is exactly how the context menu shipped
+/// broken: it worked in every test and never once on the real desktop.
+fn de_bin(name: &str) -> std::path::PathBuf {
+    if let Ok(exe) = std::env::current_exe() {
+        if let Some(dir) = exe.parent() {
+            let beside = dir.join(name);
+            if beside.exists() {
+                return beside;
+            }
+        }
+    }
+    // Fall back to PATH: a dev build run straight out of target/ has no cce
+    // binaries beside it, but does have them on PATH.
+    std::path::PathBuf::from(name)
+}
+
 /// Show the context menu for one desktop item and return the chosen action
 /// id, if any. Runs on a worker thread: it blocks until the menu closes.
 ///
@@ -326,7 +348,7 @@ pub fn save_to_desktop(bytes: &[u8], name: &str) -> std::io::Result<PathBuf> {
 pub fn item_menu(name: &str) -> Option<String> {
     use std::io::Write;
 
-    let loc = std::process::Command::new("ccectl").arg("pointer-location").output().ok()?;
+    let loc = std::process::Command::new(de_bin("ccectl")).arg("pointer-location").output().ok()?;
     let loc = String::from_utf8_lossy(&loc.stdout);
     let coord = |key: &str| -> Option<i32> {
         loc.split_whitespace()
@@ -344,7 +366,7 @@ pub fn item_menu(name: &str) -> Option<String> {
         serde_json::to_string(name).ok()?
     );
 
-    let mut child = std::process::Command::new("cce-cloud")
+    let mut child = std::process::Command::new(de_bin("cce-cloud"))
         .args(["--json", "-x", &x.to_string(), "-y", &y.to_string()])
         .stdin(std::process::Stdio::piped())
         .stdout(std::process::Stdio::piped())
@@ -362,7 +384,7 @@ pub fn item_menu(name: &str) -> Option<String> {
 /// path goes through here rather than only into the log.
 pub fn report_failure(reason: &str) {
     log::warn!("[items] drop failed: {reason}");
-    let _ = std::process::Command::new("ccectl")
+    let _ = std::process::Command::new(de_bin("ccectl"))
         .args(["notify", "Image not added to the desktop", reason])
         .stdout(std::process::Stdio::null())
         .stderr(std::process::Stdio::null())