Updated docs + added TTS backends

saiki.py

@@ -6,6 +6,8 @@ from pathlib import Path
 
 SRC_DIR = Path(__file__).resolve().parent / "src"
 if str(SRC_DIR) not in sys.path:
+    # Let the repository checkout run directly without requiring an editable
+    # install first. Installed packages will still resolve normally.
     sys.path.insert(0, str(SRC_DIR))
 
 from saiki.cli import main