feat(#79): add SQLite persistent storage for fault manager

[mfaferek93]

Pull Request

Summary

Replace in-memory storage with SQLite backend so faults survive node
restarts. Storage type is configurable via ROS parameters.

Changes:

• Add SqliteFaultStorage class implementing FaultStorage interface
• Use WAL mode for optimal write performance
• Store timestamps with nanosecond precision
• Store reporting_sources as JSON array
• Add ROS parameters: storage_type (sqlite|memory), database_path
• Default: SQLite at /var/lib/ros2_medkit/faults.db
• Auto-create database directory if needed
• Add comprehensive unit tests for SQLite storage (14 tests)
• Update integration tests to use in-memory storage for isolation
• Update README with new parameters documentation

---

Issue

Link the related issue (required):

• closes Add Persistent Storage #79

---

Type

• Bug fix
• New feature or tests
• Breaking change
• Documentation only

---

Testing

How was this tested / how should reviewers verify it?

---

Checklist

• Breaking changes are clearly described (and announced in docs / changelog if needed)
• Tests were added or updated if needed
• Docs were updated if behavior or public API changed

[Copilot]

Pull request overview

This pull request adds SQLite persistent storage to the fault manager, replacing the in-memory-only storage with a configurable backend that can use either SQLite for persistence or memory for testing/temporary use. The implementation adds a new SqliteFaultStorage class with WAL mode for performance, nanosecond timestamp precision, and JSON serialization for reporting sources.

Key changes:

• Implements SQLite-backed persistent storage with automatic database initialization and directory creation
• Adds ROS parameters (storage_type and database_path) to configure storage backend selection
• Updates integration and unit tests to use in-memory storage for test isolation

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
src/ros2_medkit_fault_manager/src/sqlite_fault_storage.cpp	New SQLite storage implementation with RAII statement wrapper, JSON array serialization, and thread-safe operations
src/ros2_medkit_fault_manager/include/ros2_medkit_fault_manager/sqlite_fault_storage.hpp	Header defining SqliteFaultStorage class interface implementing FaultStorage
src/ros2_medkit_fault_manager/src/fault_manager_node.cpp	Adds storage factory method and parameters for configurable backend selection with directory auto-creation
src/ros2_medkit_fault_manager/include/ros2_medkit_fault_manager/fault_manager_node.hpp	Updates node interface to expose storage type and use unique_ptr for polymorphic storage
src/ros2_medkit_fault_manager/test/test_sqlite_storage.cpp	Comprehensive unit tests for SQLite storage including persistence, timestamp precision, and JSON handling
src/ros2_medkit_fault_manager/test/test_integration.test.py	Updates integration tests to use memory storage for isolation
src/ros2_medkit_fault_manager/test/test_fault_manager.cpp	Updates FaultManagerNode tests to explicitly use memory storage
src/ros2_medkit_fault_manager/CMakeLists.txt	Adds SQLite3 dependency and links library, adds test_sqlite_storage target
src/ros2_medkit_fault_manager/package.xml	Adds libsqlite3-dev dependency
src/ros2_medkit_fault_manager/README.md	Documents new parameters and storage backend options with usage examples

[Copilot]

Pull request overview

Copilot reviewed 12 out of 12 changed files in this pull request and generated 6 comments.