Add comprehensive permissions management for Docker bind mounts

NEW SCRIPT: Created scripts/fix-permissions.sh - automated permission fixer

Takes ownership of repository files, makes scripts executable, sets proper permissions

Verifies permissions are correct before proceeding

DOCKER COMPOSE: Added header comments explaining permission requirements

DOCUMENTATION: Updated README.md and QUICKSTART.md with permission setup steps

WHY CRITICAL: Docker bind mounts require proper file ownership to work correctly

USER EXPERIENCE: Single command ./scripts/fix-permissions.sh handles everything

README.md

@@ -108,12 +108,24 @@ git clone https://github.com/freedbygrace/SQL.git
 cd SQL
 ```
 
-### 2. Make Scripts Executable
+### 2. Set Proper Permissions
 ```bash
-# Make all .sh files executable recursively
-find . -name "*.sh" -exec chmod +x {} \;
+# Option A: Use the automated script (recommended)
+chmod +x scripts/fix-permissions.sh
+./scripts/fix-permissions.sh
+
+# Option B: Manual setup
+sudo chown -R $USER:$USER .                    # Take ownership
+find . -name "*.sh" -exec chmod +x {} \;       # Make scripts executable
+chmod -R 755 data/ schema/ scripts/ docker/    # Set directory permissions
 ```
 
+**Why this is important:**
+- ✅ Ensures your user owns all files (prevents permission denied errors)
+- ✅ Makes all shell scripts executable
+- ✅ Allows Docker to read/write bind-mounted directories (data/, schema/, docker/)
+- ✅ Prevents "permission denied" errors with Docker volumes
+
 ### 3. Install Dependencies (Optional)
 ```bash
 # Only if you don't have Docker, psql, etc.