fix(engine): use uppercase CORTEX_HOME env var in find_cortex_home

Fixes bounty issue #1581

The find_cortex_home() function was checking for 'cortex_HOME' (mixed case)
instead of 'CORTEX_HOME' (all uppercase), causing the CORTEX_HOME environment
variable to be silently ignored. Users setting CORTEX_HOME would find that
Cortex still used the default ~/.cortex directory.

Author: factorydroid

cortex-engine/src/config/loader.rs

@@ -31,25 +31,25 @@ pub const CORTEX_CONFIG_DIR_ENV: &str = "CORTEX_CONFIG_DIR";
 /// Find the Cortex home directory.
 ///
 /// Checks in order:
-/// 1. `cortex_CONFIG_DIR` environment variable
-/// 2. `cortex_HOME` environment variable
+/// 1. `CORTEX_CONFIG_DIR` environment variable
+/// 2. `CORTEX_HOME` environment variable
 /// 3. Default `~/.cortex` directory
 pub fn find_cortex_home() -> std::io::Result<PathBuf> {
-    // Check cortex_CONFIG_DIR environment variable first (new)
+    // Check CORTEX_CONFIG_DIR environment variable first (new)
     if let Ok(val) = std::env::var(CORTEX_CONFIG_DIR_ENV)
         && !val.is_empty()
     {
         let path = PathBuf::from(&val);
-        debug!(path = %path.display(), "Using cortex_CONFIG_DIR");
+        debug!(path = %path.display(), "Using CORTEX_CONFIG_DIR");
         return Ok(path);
     }
 
-    // Check cortex_HOME environment variable
-    if let Ok(val) = std::env::var("cortex_HOME")
+    // Check CORTEX_HOME environment variable
+    if let Ok(val) = std::env::var("CORTEX_HOME")
         && !val.is_empty()
     {
         let path = PathBuf::from(&val);
-        debug!(path = %path.display(), "Using cortex_HOME");
+        debug!(path = %path.display(), "Using CORTEX_HOME");
         return Ok(path);
     }