added api for ai; got backend working

src-tauri/src/paths.rs

@@ -0,0 +1,30 @@
+use std::path::PathBuf;
+
+/// Resolve the project root from the executable path.
+/// In dev mode, the binary lives at: <root>/src-tauri/target/debug/<bin>
+/// So the project root is 4 levels above the binary.
+pub fn project_root() -> PathBuf {
+    let exe = std::env::current_exe().expect("Failed to get executable path");
+    // exe -> debug/ -> target/ -> src-tauri/ -> root
+    exe.parent()
+        .and_then(|p| p.parent())
+        .and_then(|p| p.parent())
+        .and_then(|p| p.parent())
+        .map(|p| p.to_path_buf())
+        .unwrap_or_else(|| PathBuf::from("."))
+}
+
+/// Absolute path to the venv Python 3.10 interpreter.
+pub fn python_exe() -> PathBuf {
+    project_root().join(".venv/bin/python3.10")
+}
+
+/// Absolute path to a script in the backend directory.
+pub fn backend_script(name: &str) -> PathBuf {
+    project_root().join("backend").join(name)
+}
+
+/// Absolute path to a script at the project root.
+pub fn root_script(name: &str) -> PathBuf {
+    project_root().join(name)
+}