Add @persist decorator with FlowPersistence interface (#1892)

* Add @persist decorator with SQLite persistence

- Add FlowPersistence abstract base class
- Implement SQLiteFlowPersistence backend
- Add @persist decorator for flow state persistence
- Add tests for flow persistence functionality

Co-Authored-By: Joe Moura <joao@crewai.com>

* Fix remaining merge conflicts in uv.lock

- Remove stray merge conflict markers
- Keep main's comprehensive platform-specific resolution markers
- Preserve all required dependencies for persistence functionality

Co-Authored-By: Joe Moura <joao@crewai.com>

* Fix final CUDA dependency conflicts in uv.lock

- Resolve NVIDIA CUDA solver dependency conflicts
- Use main's comprehensive platform checks
- Ensure all merge conflict markers are removed
- Preserve persistence-related dependencies

Co-Authored-By: Joe Moura <joao@crewai.com>

* Fix nvidia-cusparse-cu12 dependency conflicts in uv.lock

- Resolve NVIDIA CUSPARSE dependency conflicts
- Use main's comprehensive platform checks
- Complete systematic check of entire uv.lock file
- Ensure all merge conflict markers are removed

Co-Authored-By: Joe Moura <joao@crewai.com>

* Fix triton filelock dependency conflicts in uv.lock

- Resolve triton package filelock dependency conflict
- Use main's comprehensive platform checks
- Complete final systematic check of entire uv.lock file
- Ensure TOML file structure is valid

Co-Authored-By: Joe Moura <joao@crewai.com>

* Fix merge conflict in crew_test.py

- Remove duplicate assertion in test_multimodal_agent_live_image_analysis
- Clean up conflict markers
- Preserve test functionality

Co-Authored-By: Joe Moura <joao@crewai.com>

* Clean up trailing merge conflict marker in crew_test.py

- Remove remaining conflict marker at end of file
- Preserve test functionality
- Complete conflict resolution

Co-Authored-By: Joe Moura <joao@crewai.com>

* Improve type safety in persistence implementation and resolve merge conflicts

Co-Authored-By: Joe Moura <joao@crewai.com>

* fix: Add explicit type casting in _create_initial_state method

Co-Authored-By: Joe Moura <joao@crewai.com>

* fix: Improve type safety in flow state handling with proper validation

Co-Authored-By: Joe Moura <joao@crewai.com>

* fix: Improve type system with proper TypeVar scoping and validation

Co-Authored-By: Joe Moura <joao@crewai.com>

* fix: Improve state restoration logic and add comprehensive tests

Co-Authored-By: Joe Moura <joao@crewai.com>

* fix: Initialize FlowState instances without passing id to constructor

Co-Authored-By: Joe Moura <joao@crewai.com>

* feat: Add class-level flow persistence decorator with SQLite default

- Add class-level @persist decorator support
- Set SQLiteFlowPersistence as default backend
- Use db_storage_path for consistent database location
- Improve async method handling and type safety
- Add comprehensive docstrings and examples

Co-Authored-By: Joe Moura <joao@crewai.com>

* fix: Sort imports in decorators.py to fix lint error

Co-Authored-By: Joe Moura <joao@crewai.com>

* style: Organize imports according to PEP 8 standard

Co-Authored-By: Joe Moura <joao@crewai.com>

* style: Format typing imports with line breaks for better readability

Co-Authored-By: Joe Moura <joao@crewai.com>

* style: Simplify import organization to fix lint error

Co-Authored-By: Joe Moura <joao@crewai.com>

* style: Fix import sorting using Ruff auto-fix

Co-Authored-By: Joe Moura <joao@crewai.com>

---------

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
Co-authored-by: Joe Moura <joao@crewai.com>
Co-authored-by: João Moura <joaomdmoura@gmail.com>

src/crewai/utilities/paths.py

@@ -5,14 +5,18 @@ import appdirs
 
 """Path management utilities for CrewAI storage and configuration."""
 
-def db_storage_path():
-    """Returns the path for database storage."""
+def db_storage_path() -> str:
+    """Returns the path for SQLite database storage.
+    
+    Returns:
+        str: Full path to the SQLite database file
+    """
     app_name = get_project_directory_name()
     app_author = "CrewAI"
 
     data_dir = Path(appdirs.user_data_dir(app_name, app_author))
     data_dir.mkdir(parents=True, exist_ok=True)
-    return data_dir
+    return str(data_dir / "crewai_flows.db")
 
 
 def get_project_directory_name():