feat: Introduce mock ROM mode for testing without actual ROM files

- Added a new feature to the `z3ed` AI agent allowing testing in mock ROM mode, which creates a minimal valid ROM structure with embedded labels but no actual game data.
- Updated the `agent_test_suite.sh` script to default to mock ROM mode for easier testing.
- Introduced `--mock-rom` command line flag to enable mock ROM mode in various agent commands.
- Enhanced documentation to cover the usage and benefits of mock ROM mode for CI/CD and development testing.
- Implemented necessary changes in the codebase to support mock ROM initialization and label management.

src/cli/flags.cc

@@ -3,6 +3,9 @@
 #include "absl/flags/flag.h"
 
 ABSL_FLAG(std::string, rom, "", "Path to the ROM file");
+ABSL_FLAG(bool, mock_rom, false,
+          "Use mock ROM mode for testing without requiring an actual ROM file. "
+          "Loads all Zelda3 embedded labels but no actual ROM data.");
 
 // AI Service Configuration Flags
 ABSL_FLAG(std::string, ai_provider, "auto",