refactor: [30388f42] Entferne Legacy-Token-Dateien und Abhängigkeiten

- Bereinigt alle Dockerfiles (market, content, b2b) von COPY gemini_api_key.txt.
- Aktualisiert market_intel_orchestrator.py und b2b_marketing_orchestrator.py, um API-Keys strikt aus Umgebungsvariablen zu lesen.
- Verhindert Build-Fehler durch fehlende lokale Token-Dateien.

b2b-marketing-assistant/b2b_marketing_orchestrator.py

@@ -333,12 +333,11 @@ PROMPTS = {
 # --- API & SCRAPING HELPERS ---
 
 def load_api_key():
-    try:
-        with open("gemini_api_key.txt", "r") as f:
-            return f.read().strip()
-    except FileNotFoundError:
-        logging.error("API key file 'gemini_api_key.txt' not found.")
+    api_key = os.getenv("GEMINI_API_KEY")
+    if not api_key:
+        logging.error("GEMINI_API_KEY environment variable not found.")
         return None
+    return api_key
 
 def call_gemini_api(prompt, api_key, retries=3):
     url = f"https://generativelanguage.googleapis.com/v1/models/gemini-2.5-flash:generateContent?key={api_key}"