feat(utils): add compare-dirs.sh utility

- recursive directory comparison based on source folder
- support for quiet mode and custom log files
- colored output and dependency checking
- integrated with main navigation table

tools/linux/compare-dirs/README.md

@@ -0,0 +1,37 @@
+# 🛠 Directory Comparator
+
+A robust Bash utility for recursive file comparison between two directories. It uses DIR_A as the source of truth for file names and checks for their existence and differences in DIR_B. Perfect for auditing configuration changes or verifying backup integrity.
+
+---
+
+### ⚙️ Prerequisites
+* **diff:** Used for generating file differences.
+* **find:** Required for recursive file discovery.
+* **Bash 4+:** Utilizes modern bash features like `set -euo pipefail`.
+
+### 📊 Parameters Mapping
+| Option | Description |
+| :--- | :--- |
+| -o <file>	| Save the full report to a specific file (default: `./compare-dirs.log`). |
+| -q	| Quiet mode: Show only the final summary without full `diff` output. |
+| -h	| Show help and usage information. |
+
+### 🏃 Quick Start
+```bash
+    # Basic comparison (outputs diffs to terminal and compare-dirs.log)
+    ./compare-dirs.sh /path/to/dir_a /path/to/dir_b
+
+    # Quiet mode (summary only) with custom log file
+    ./compare-dirs.sh -q -o audit_report.log /etc/nginx /backup/nginx
+```
+
+### 🛡 Features
+* **Safe Discovery:** Uses `-printf '%P\0'` with `find` to safely handle filenames with spaces or special characters.
+* **Strict Execution:** Built-in error trapping and strict mode to prevent silent failures.
+* **Colorized UI:** Visual feedback for **IDENTICAL**, **DIFFERENT**, and **MISSING** status.
+* **Log Rotation Ready:** Outputs to both `STDOUT` and log files simultaneously.
+
+---
+
+### ⚖️ License
+MIT [LICENSE](https://github.com/andsyrovatko/s4k-admin-toolbox/blob/main/LICENSE). Free to use and modify.