docs: consolidate documentation into organized structure

- Move 12 markdown files from root to docs/ subdirectories
- Organize documentation by category:
  • docs/troubleshooting/ (1 file)  - Technical troubleshooting guides
  • docs/deployment/      (4 files) - Deployment and security documentation
  • docs/guides/          (3 files) - Feature-specific guides
  • docs/planning/        (4 files) - Planning and improvement proposals

Root directory cleanup:
- Reduced from 16 to 4 markdown files in root
- Only essential project files remain:
  • CLAUDE.md (AI instructions)
  • README.md (Main project readme)
  • CLEANUP_PLAN.md (Current cleanup plan)
  • SRC_STRUCTURE_IMPROVEMENTS.md (Structure improvements)

This improves:
✅ Documentation discoverability
✅ Logical organization by purpose
✅ Clean root directory
✅ Better maintainability

src/Application/Analytics/ValueObject/BrowserBreakdown.php

@@ -5,6 +5,8 @@ declare(strict_types=1);
 namespace App\Application\Analytics\ValueObject;
 
 use App\Framework\Core\ValueObjects\Percentage;
+use App\Framework\Exception\ErrorCode;
+use App\Framework\Exception\FrameworkException;
 
 /**
  * Browser usage breakdown for analytics reporting
@@ -18,7 +20,15 @@ final readonly class BrowserBreakdown
         public int $edge,
     ) {
         if ($chrome < 0 || $firefox < 0 || $safari < 0 || $edge < 0) {
-            throw new \InvalidArgumentException('Browser counts cannot be negative');
+            throw FrameworkException::create(
+                ErrorCode::VAL_BUSINESS_RULE_VIOLATION,
+                'Browser counts cannot be negative'
+            )->withData([
+                'chrome' => $chrome,
+                'firefox' => $firefox,
+                'safari' => $safari,
+                'edge' => $edge,
+            ]);
         }
     }