Replace unsafe string concatenation patterns using strcpy/strcat with explicit memcpy calls and proper null-termination in bash_repair.c, context_manager.c, context_summarizer.c, and db.c. Add missing null-pointer checks for strdup results in bash_executor.c. Introduce atomic_int for spinner_running flag in http_client.c. Add consecutive_tool_error_iterations field to agent struct and refactor agent heartbeat/token tracking to use messages_get_db instead of db_open. Remove r_config_get_max_tokens declaration from r_config.h. Add json_repair.c to Makefile build sources and include db.h in messages.h with new messages_get_db function declaration.
