feat: Add comprehensive documentation suite and reorganize project structure

- Created complete documentation in docs/ directory
- Added PROJECT_OVERVIEW.md with feature highlights and getting started guide
- Added ARCHITECTURE.md with system design and technical details
- Added SECURITY.md with comprehensive security implementation guide
- Added DEVELOPMENT.md with development workflows and best practices
- Added DEPLOYMENT.md with production deployment instructions
- Added API.md with complete REST API documentation
- Added CONTRIBUTING.md with contribution guidelines
- Added CHANGELOG.md with version history and migration notes
- Reorganized all documentation files into docs/ directory for better organization
- Updated README.md with proper documentation links and quick navigation
- Enhanced project structure with professional documentation standards

f_scripts/combine_sql.php

@@ -0,0 +1,54 @@
+<?php
+// Combine all SQL fragments into __install/easystream.sql
+// Usage: php f_scripts/combine_sql.php
+
+declare(strict_types=1);
+
+$root = realpath(__DIR__ . '/..');
+$installDir = $root . DIRECTORY_SEPARATOR . '__install';
+$deployDir  = $root . DIRECTORY_SEPARATOR . 'deploy';
+$baseFile   = $installDir . DIRECTORY_SEPARATOR . 'easystream.sql';
+$backupFile = $installDir . DIRECTORY_SEPARATOR . 'easystream.sql.backup';
+
+if (!file_exists($baseFile)) {
+    fwrite(STDERR, "Base SQL not found: {$baseFile}\n");
+    exit(1);
+}
+
+$fragments = [
+    $installDir . DIRECTORY_SEPARATOR . 'install_settings_system.sql',
+    $installDir . DIRECTORY_SEPARATOR . 'updatedb_site.sql',
+    $installDir . DIRECTORY_SEPARATOR . 'updatedb_chat.sql',
+    $deployDir  . DIRECTORY_SEPARATOR . 'create_social_tables.sql',
+];
+
+// Read base
+$base = file_get_contents($baseFile);
+if ($base === false) {
+    fwrite(STDERR, "Failed to read base SQL file.\n");
+    exit(1);
+}
+
+// Backup current base
+@copy($baseFile, $backupFile);
+
+$combined = rtrim($base) . "\n\n-- =====================================================================\n-- Combined migrations appended by f_scripts/combine_sql.php\n-- Timestamp: " . date('c') . "\n-- =====================================================================\n\n";
+
+foreach ($fragments as $frag) {
+    if (!file_exists($frag)) { continue; }
+    $sz = filesize($frag);
+    if ($sz === false || $sz === 0) { continue; }
+    $content = file_get_contents($frag);
+    if ($content === false) { continue; }
+    $combined .= "\n\n-- >>> BEGIN: " . basename($frag) . "\n\n" . trim($content) . "\n\n-- <<< END: " . basename($frag) . "\n";
+}
+
+// Write back
+if (file_put_contents($baseFile, $combined) === false) {
+    fwrite(STDERR, "Failed to write combined SQL file.\n");
+    exit(1);
+}
+
+echo "Combined SQL written to: {$baseFile}\nBackup saved to: {$backupFile}\n";
+exit(0);
+