fix: Restore all files lost during destructive rebase

A previous `git pull --rebase origin main` dropped 177 local commits,
losing 3400+ files across admin-v2, backend, studio-v2, website,
klausur-service, and many other services. The partial restore attempt
(660295e2) only recovered some files.

This commit restores all missing files from pre-rebase ref 98933f5e
while preserving post-rebase additions (night-scheduler, night-mode UI,
NightModeWidget dashboard integration).

Restored features include:
- AI Module Sidebar (FAB), OCR Labeling, OCR Compare
- GPU Dashboard, RAG Pipeline, Magic Help
- Klausur-Korrektur (8 files), Abitur-Archiv (5+ files)
- Companion, Zeugnisse-Crawler, Screen Flow
- Full backend, studio-v2, website, klausur-service
- All compliance SDKs, agent-core, voice-service
- CI/CD configs, documentation, scripts

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

school-service/internal/config/config.go

@@ -0,0 +1,103 @@
+package config
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/joho/godotenv"
+)
+
+// Config holds all configuration for the school service
+type Config struct {
+	// Server
+	Port        string
+	Environment string
+
+	// Database
+	DatabaseURL string
+
+	// JWT
+	JWTSecret string
+
+	// CORS
+	AllowedOrigins []string
+
+	// Rate Limiting
+	RateLimitRequests int
+	RateLimitWindow   int // in seconds
+
+	// LLM Gateway (for AI features)
+	LLMGatewayURL string
+}
+
+// Load loads configuration from environment variables
+func Load() (*Config, error) {
+	// Load .env file if exists (for development)
+	_ = godotenv.Load()
+
+	cfg := &Config{
+		Port:              getEnv("PORT", "8084"),
+		Environment:       getEnv("ENVIRONMENT", "development"),
+		DatabaseURL:       getEnv("DATABASE_URL", ""),
+		JWTSecret:         getEnv("JWT_SECRET", ""),
+		RateLimitRequests: getEnvInt("RATE_LIMIT_REQUESTS", 100),
+		RateLimitWindow:   getEnvInt("RATE_LIMIT_WINDOW", 60),
+		LLMGatewayURL:     getEnv("LLM_GATEWAY_URL", "http://backend:8000/llm"),
+	}
+
+	// Parse allowed origins
+	originsStr := getEnv("ALLOWED_ORIGINS", "http://localhost:3000,http://localhost:8000")
+	cfg.AllowedOrigins = parseCommaSeparated(originsStr)
+
+	// Validate required fields
+	if cfg.DatabaseURL == "" {
+		return nil, fmt.Errorf("DATABASE_URL is required")
+	}
+
+	if cfg.JWTSecret == "" {
+		return nil, fmt.Errorf("JWT_SECRET is required")
+	}
+
+	return cfg, nil
+}
+
+func getEnv(key, defaultValue string) string {
+	if value := os.Getenv(key); value != "" {
+		return value
+	}
+	return defaultValue
+}
+
+func getEnvInt(key string, defaultValue int) int {
+	if value := os.Getenv(key); value != "" {
+		var result int
+		fmt.Sscanf(value, "%d", &result)
+		return result
+	}
+	return defaultValue
+}
+
+func parseCommaSeparated(s string) []string {
+	if s == "" {
+		return []string{}
+	}
+	var result []string
+	start := 0
+	for i := 0; i <= len(s); i++ {
+		if i == len(s) || s[i] == ',' {
+			item := s[start:i]
+			// Trim whitespace
+			for len(item) > 0 && item[0] == ' ' {
+				item = item[1:]
+			}
+			for len(item) > 0 && item[len(item)-1] == ' ' {
+				item = item[:len(item)-1]
+			}
+			if item != "" {
+				result = append(result, item)
+			}
+			start = i + 1
+		}
+	}
+	return result
+}