fix: auto-discover localllm binary in target/release and PATH

tauri-app/src-tauri/src/lib.rs

@@ -1,4 +1,4 @@
-use std::path::Path;
+use std::path::{Path, PathBuf};
 use std::process::{Child, Command};
 use std::sync::Mutex;
 use tauri::{AppHandle, Manager, State};
@@ -47,6 +47,56 @@ fn query_gpu() -> Result<GpuInfo, String> {
 
 // ─── Server lifecycle ─────────────────────────────────────────────────────────
 
+/// Locate the `localllm` binary by searching several well-known locations:
+/// 1. Workspace `target/release/` relative to the Tauri app's source tree
+/// 2. Next to the running executable (for installed/bundled builds)
+/// 3. System PATH
+fn find_localllm_binary() -> Option<PathBuf> {
+    let exe_name = if cfg!(target_os = "windows") { "localllm.exe" } else { "localllm" };
+
+    // 1. Workspace target/release — works when running `npm run tauri dev` from tauri-app/
+    //    The Tauri dev binary lives at tauri-app/src-tauri/target/debug/forgelm-chat.exe
+    //    so we walk up to find the workspace root and look for target/release/localllm.exe
+    if let Ok(exe) = std::env::current_exe() {
+        // Walk up from the current exe looking for target/release/localllm.exe
+        let mut dir = exe.parent();
+        while let Some(d) = dir {
+            let candidate = d.join("target").join("release").join(exe_name);
+            if candidate.exists() {
+                return Some(candidate);
+            }
+            // Also check sibling: if we're inside target/debug, go up two levels
+            let candidate2 = d.join(exe_name);
+            if candidate2.exists() {
+                return Some(candidate2);
+            }
+            dir = d.parent();
+        }
+    }
+
+    // 2. Relative to CWD (useful when launched from repo root)
+    let cwd_candidate = PathBuf::from("target").join("release").join(exe_name);
+    if cwd_candidate.exists() {
+        return Some(cwd_candidate);
+    }
+
+    // 3. System PATH
+    if let Ok(output) = Command::new(if cfg!(target_os = "windows") { "where" } else { "which" })
+        .arg("localllm")
+        .output()
+    {
+        if output.status.success() {
+            let path_str = String::from_utf8_lossy(&output.stdout);
+            let first_line = path_str.lines().next().unwrap_or("").trim();
+            if !first_line.is_empty() {
+                return Some(PathBuf::from(first_line));
+            }
+        }
+    }
+
+    None
+}
+
 #[tauri::command]
 fn start_server(
     state: State<ServerState>,
@@ -60,15 +110,20 @@ fn start_server(
         return Err("Server is already running".into());
     }
 
-    let binary = if cfg!(target_os = "windows") { "localllm.exe" } else { "localllm" };
+    let binary_path = find_localllm_binary()
+        .ok_or_else(|| {
+            "localllm binary not found. Build it with: cargo build --release -p inference-server\n\
+             Then ensure the binary is in one of: target/release/, PATH, or next to this app."
+                .to_string()
+        })?;
 
-    let child = Command::new(binary)
+    let child = Command::new(&binary_path)
         .env("LOCALLLM_MODEL", &model_path)
         .env("LOCALLLM_ADDR", &addr)
         .env("LOCALLLM_GPU_LAYERS", gpu_layers.to_string())
         .env("LOCALLLM_CTX", ctx_size.to_string())
         .spawn()
-        .map_err(|e| format!("Failed to start server: {e}"))?;
+        .map_err(|e| format!("Failed to start server ({}): {e}", binary_path.display()))?;
 
     let pid = child.id();
     *guard = Some(child);
@@ -275,6 +330,17 @@ fn load_config(app: AppHandle) -> Result<AppConfig, String> {
     serde_json::from_str(&json).map_err(|e| format!("Parse error: {e}"))
 }
 
+/// Returns the resolved path to the localllm binary (useful for debugging).
+#[tauri::command]
+fn find_server_binary() -> Result<String, String> {
+    find_localllm_binary()
+        .map(|p| p.to_string_lossy().to_string())
+        .ok_or_else(|| {
+            "localllm binary not found. Build with: cargo build --release -p inference-server"
+                .to_string()
+        })
+}
+
 /// Returns the app data directory path (useful for debugging).
 #[tauri::command]
 fn get_app_data_dir(app: AppHandle) -> Result<String, String> {
@@ -304,6 +370,7 @@ pub fn run() {
             save_config,
             load_config,
             get_app_data_dir,
+            find_server_binary,
         ])
         .setup(|app| {
             #[cfg(debug_assertions)]