fix: add missing projects.py to worktree

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

src/zotero_kb/projects.py

@@ -0,0 +1,67 @@
+from __future__ import annotations
+
+import json
+from pathlib import Path
+
+
+class ProjectService:
+    def __init__(self, workspace_dir: Path) -> None:
+        self.workspace_dir = workspace_dir
+        self.projects_dir = workspace_dir / "projects"
+        self.index_dir = workspace_dir / "library" / "index"
+
+    def add_items(self, project_id: str, item_keys: list[str]) -> dict[str, object]:
+        selected_items = self._read_selected_items(project_id)
+        selected_items = sorted(set(selected_items + item_keys))
+        self._write_json(self._project_dir(project_id) / "selected-items.json", selected_items)
+        return self._rebuild_project_index(project_id, selected_items)
+
+    def remove_item(self, project_id: str, item_key: str) -> dict[str, object]:
+        selected_items = [key for key in self._read_selected_items(project_id) if key != item_key]
+        self._write_json(self._project_dir(project_id) / "selected-items.json", selected_items)
+        return self._rebuild_project_index(project_id, selected_items)
+
+    def get_project_view(self, project_id: str) -> dict[str, object]:
+        index_path = self._project_dir(project_id) / "project-index.json"
+        if not index_path.exists():
+            selected_items = self._read_selected_items(project_id)
+            return self._rebuild_project_index(project_id, selected_items)
+        return json.loads(index_path.read_text(encoding="utf-8"))
+
+    def _rebuild_project_index(self, project_id: str, selected_items: list[str]) -> dict[str, object]:
+        cards_index = self._read_json(self.index_dir / "cards.json")
+        collections_index = self._read_json(self.index_dir / "collections.json")
+        project_cards = [cards_index[item_key] for item_key in selected_items if item_key in cards_index]
+        project_collections = [
+            payload
+            for payload in collections_index.values()
+            if set(payload.get("item_keys", [])) & set(selected_items)
+        ]
+        payload = {
+            "project_id": project_id,
+            "selected_items": selected_items,
+            "cards": project_cards,
+            "collections": project_collections,
+        }
+        self._write_json(self._project_dir(project_id) / "project-index.json", payload)
+        return payload
+
+    def _read_selected_items(self, project_id: str) -> list[str]:
+        path = self._project_dir(project_id) / "selected-items.json"
+        if not path.exists():
+            return []
+        return [str(value) for value in json.loads(path.read_text(encoding="utf-8"))]
+
+    def _project_dir(self, project_id: str) -> Path:
+        return self.projects_dir / project_id
+
+    @staticmethod
+    def _read_json(path: Path) -> dict[str, object]:
+        if not path.exists():
+            return {}
+        return json.loads(path.read_text(encoding="utf-8"))
+
+    @staticmethod
+    def _write_json(path: Path, payload: object) -> None:
+        path.write_text(json.dumps(payload, indent=2, ensure_ascii=False) + "\n", encoding="utf-8")
+