User Management + Didaktisches Handbuch + Stadt-Editor + Emoji-Kacheln

User Management (Backend):
- schema-v2.sql: students, licenses, student_results, activity_log Tabellen
- auth.php: Lehrer-Registrierung/Login, Schueler-Login, Status-Check
- classes.php: CRUD fuer Klassenverwaltung (mit Join-Code-Generator)
- students.php: Schueler erstellen (einzeln + Batch), bearbeiten, loeschen
- modules.php: Modulfreigabe pro Klasse (locked/free/teacher_started)

Didaktisches Handbuch:
- handbuch.html: Vollstaendiger Lehrpersonen-Guide
- 6 Module detailliert beschrieben (Lernziele, Kompetenzen)
- Vor/Nach-Fragen fuer jede Simulation
- Empfohlener Unterrichtsablauf (45-min-Einheit)
- Differenzierungshinweise, Bewertungsempfehlungen

Stadt-Editor:
- stadt-editor.html: Funktionierendes 8x8 Raster mit Kachel-Platzierung
- 15 Emoji-Gebaude-Kacheln (Kirche, Moschee, Wohngebiet, Fabrik, etc.)
- Spielplatz: Rutsche+Karussell statt schwebende Koepfe
- Hochhaeuser: 6 Gebaeude in 2 Reihen

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

App/schema-v2.sql

@@ -0,0 +1,72 @@
+-- GeoGraSim — Schema V2: Vollstaendiges User Management
+-- Fuehre NACH schema.sql aus: mysql -u root geograsim < schema-v2.sql
+
+USE geograsim;
+
+-- Lehrkraefte erweitern um E-Mail (ignoriere Fehler wenn Spalte schon existiert)
+ALTER TABLE teachers ADD COLUMN email VARCHAR(255) UNIQUE AFTER username;
+ALTER TABLE teachers ADD COLUMN email_verified BOOLEAN DEFAULT FALSE AFTER email;
+ALTER TABLE teachers ADD COLUMN school_name VARCHAR(255) AFTER display_name;
+ALTER TABLE teachers ADD COLUMN reset_token VARCHAR(64) AFTER email_verified;
+ALTER TABLE teachers ADD COLUMN reset_expires TIMESTAMP NULL AFTER reset_token;
+
+-- Schueler als echte Accounts (nicht nur Sessions)
+CREATE TABLE IF NOT EXISTS students (
+  id           INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
+  class_id     INT UNSIGNED NOT NULL,
+  username     VARCHAR(64) NOT NULL,
+  password     VARCHAR(255) NOT NULL,
+  display_name VARCHAR(128),
+  is_anonymous BOOLEAN DEFAULT TRUE,   -- true = Pseudonym, false = echter Name
+  created_at   TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+  last_login   TIMESTAMP NULL,
+  UNIQUE KEY uq_class_user (class_id, username),
+  FOREIGN KEY (class_id) REFERENCES classes(id) ON DELETE CASCADE
+) ENGINE=InnoDB;
+
+-- Lizenzen
+CREATE TABLE IF NOT EXISTS licenses (
+  id           INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
+  code         VARCHAR(32) NOT NULL UNIQUE,
+  teacher_id   INT UNSIGNED,           -- NULL = noch nicht eingeloest
+  max_students INT UNSIGNED DEFAULT 30,
+  valid_from   DATE NOT NULL,
+  valid_until  DATE NOT NULL,
+  created_at   TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+  redeemed_at  TIMESTAMP NULL,
+  FOREIGN KEY (teacher_id) REFERENCES teachers(id) ON DELETE SET NULL
+) ENGINE=InnoDB;
+
+-- Modulfreigabe erweitern
+ALTER TABLE class_modules ADD COLUMN mode ENUM('locked','free','teacher_started') DEFAULT 'locked' AFTER enabled;
+ALTER TABLE class_modules ADD COLUMN started_at TIMESTAMP NULL AFTER mode;
+ALTER TABLE class_modules ADD COLUMN due_date TIMESTAMP NULL AFTER started_at;
+
+-- Schueler-Ergebnisse (verknuepft mit Schueler-Account, nicht nur Session)
+CREATE TABLE IF NOT EXISTS student_results (
+  id           INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
+  student_id   INT UNSIGNED NOT NULL,
+  class_id     INT UNSIGNED NOT NULL,
+  module_id    VARCHAR(16) NOT NULL,
+  score        DECIMAL(5,2),           -- 0-100
+  balance_idx  DECIMAL(5,2),           -- 0-100
+  duration_sec INT UNSIGNED,
+  detail_json  JSON,                   -- Modulspezifische Details
+  completed_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+  INDEX idx_student (student_id),
+  INDEX idx_class_module (class_id, module_id),
+  FOREIGN KEY (student_id) REFERENCES students(id) ON DELETE CASCADE,
+  FOREIGN KEY (class_id) REFERENCES classes(id) ON DELETE CASCADE
+) ENGINE=InnoDB;
+
+-- Aktivitaetslog (wer hat wann was gemacht)
+CREATE TABLE IF NOT EXISTS activity_log (
+  id           INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,
+  user_type    ENUM('teacher','student') NOT NULL,
+  user_id      INT UNSIGNED NOT NULL,
+  action       VARCHAR(64) NOT NULL,   -- 'login','start_module','complete_module','view_results'
+  detail       VARCHAR(255),
+  created_at   TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+  INDEX idx_user (user_type, user_id),
+  INDEX idx_time (created_at)
+) ENGINE=InnoDB;