feat(v3.1): Major architectural refactoring, multi-system compatibility, JSON engine & CLI automation

[aagrandaz]

🚀 Overview & Motivation

This PR introduces a major architectural evolution (v3.1 Next-Gen) for the **MacBook Optimization Script**. It enhances system stability,      

respects Apple Security models (SIP & SSV), adds exact user state backup/rollback, and provides non-interactive CLI automation capabilities.

## ✨ Key Features & Enhancements                                                                                                              
- 💻 **Multi-System Detection (`sys_compat.sh`):** Automatic detection for macOS Catalina (10.15) up to macOS 15+ (Sequoia), Apple Silicon     

(arm64), Intel (x86_64), SIP, and SSV read-only /System protection.
- 🛡️ Signal Traps & Safety (trap_handler.sh): Graceful SIGINT/SIGTERM handling, automatic terminal cursor/color restoration, and PID
process lockfile to prevent race conditions.
- 💾 Exact User Backup & Rollback (backup.sh & rollback.sh): Backs up original user defaults, sysctl, and pmset keys before
mutation, allowing 100% exact state restoration.
- 📊 Native JSON Engine (json_engine.sh): Dual state logging in text format and structured JSON (~/.macbook_optimizer_state.json)
parsed via native AWK.
- 🤖 Non-Interactive CLI Suite (script.sh): Added --dry-run, --all, --module, --status, --rollback, --lang, --check-update,
and --update.
- ⚡ Concurrent Diagnostics & Benchmarks (parallel_diag.sh & benchmark.sh): Parallel background diagnostic loading and quantitative
DNS/Disk performance test suite with ASCII tables.
- ⏰ Automated Scheduler (scheduler.sh): Optional macOS LaunchAgent daemon for background weekly maintenance.
- 🌐 Multilingual UI (i18n.sh): Real-time language switching between English and Spanish.
- 🧪 Test Suite & Docs: Includes automated test suite (tests/test_modules.sh, 8 Passed/0 Failed) and DOCUMENTATION_V3.md.

## 🧪 Testing Verification                                                                                                                     
- Ran syntax validation across all shell scripts (`bash -n`).                                                                                  
- Executed non-destructive simulation (`./script.sh --dry-run --all`).                                                                         
- All 8 integration tests passed (`./tests/test_modules.sh`).