refactor: rename canto-backend → backend, canto-frontend → frontend

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/core/progress_store.py

@@ -0,0 +1,38 @@
+from typing import Dict
+
+_store: Dict[str, dict] = {}
+
+
+def _ensure(key: str) -> dict:
+    if key not in _store:
+        _store[key] = {"lines": [], "done": False}
+    return _store[key]
+
+
+def reset(key: str) -> None:
+    _store[key] = {"lines": [], "done": False}
+
+
+def append_line(key: str, text: str) -> None:
+    s = _ensure(key)
+    s["lines"].append(text)
+
+
+def append_token(key: str, token: str) -> None:
+    s = _ensure(key)
+    if s["lines"]:
+        s["lines"][-1] += token
+    else:
+        s["lines"].append(token)
+
+
+def mark_done(key: str) -> None:
+    s = _ensure(key)
+    s["done"] = True
+
+
+def get_snapshot(key: str) -> dict:
+    s = _store.get(key)
+    if not s:
+        return {"lines": [], "done": True}
+    return {"lines": list(s["lines"]), "done": s["done"]}