Introduce swap journaling crash recovery system with tests.

- Added detailed journaling system (`SwapManager`) for crash recovery, including edit recording and replay.
- Integrated recovery prompts for handling swap files during file open flows.
- Implemented swap file cleanup, checkpointing, and compaction mechanisms.
- Added extensive unit tests for swap-related behaviors such as recovery prompts, file pruning, and corruption handling.
- Updated CMake to include new test files.

Buffer.h

@@ -494,6 +494,12 @@ public:
 	}
 
 
+	[[nodiscard]] kte::SwapRecorder *SwapRecorder() const
+	{
+		return swap_rec_;
+	}
+
+
 	// Raw, low-level editing APIs used by UndoSystem apply().
 	// These must NOT trigger undo recording. They also do not move the cursor.
 	void insert_text(int row, int col, std::string_view text);
@@ -508,6 +514,11 @@ public:
 
 	void delete_row(int row);
 
+	// Replace the entire buffer content with raw bytes.
+	// Intended for crash recovery (swap replay) and test harnesses.
+	// This does not trigger swap or undo recording.
+	void replace_all_bytes(std::string_view bytes);
+
 	// Undo system accessors (created per-buffer)
 	[[nodiscard]] UndoSystem *Undo();