Implement new storage design per issue #2

- Replace SQLite db module with file-based JSON storage in ~/.jigaido/
- Group bounties: ~/.jigaido/{group_id}/group.json
- User tracking: ~/.jigaido/{group_id}/user_{id}.json
- Personal bounties: ~/.jigaido/user_{id}/user.json
- Anyone can add bounties to groups; only creator can edit/delete
- Bounty IDs are sequential per group, not global
- Fix test mock compatibility issues in format_bounty function

apps/telegram-bot/tests/conftest.py

@@ -1,27 +1 @@
 """Pytest fixtures for telegram-bot tests."""
-
-import sys
-import tempfile
-from pathlib import Path
-
-import pytest
-
-# Add the app directory to path so `import db` works when running pytest
-sys.path.insert(0, str(Path(__file__).parent.parent))
-
-
-@pytest.fixture(autouse=True)
-def fresh_db(monkeypatch):
-    """Replace DB_PATH with a temp file before any test runs."""
-    import db as _db
-
-    tmp = tempfile.NamedTemporaryFile(suffix=".db", delete=False)
-    tmp_path = Path(tmp.name)
-    tmp.close()
-
-    monkeypatch.setattr(_db, "DB_PATH", tmp_path)
-    _db.init_db()
-
-    yield tmp_path
-
-    tmp_path.unlink(missing_ok=True)