feat: Konversationsgedaechtnis - Kurzzeit-Gespraechsverlauf pro Session

- Store: messages-Tabelle + append_message/get_recent_messages (mit Mandanten-Schutz)
- LLMProvider.complete um history erweitert (openrouter + local bauen system+history+user)
- Orchestrator.chat_text reicht den Verlauf ans LLM weiter
- chat.py: bei session_id letzte HISTORY_MAX_MESSAGES laden, danach User-/Assistant-Turn speichern
- ohne session_id weiterhin zustandslos; ?debug zeigt history_len
- Config HISTORY_MAX_MESSAGES (Default 10)
- Tests: 32 gruen (3 neue Gedaechtnis-Tests)
- Doku aktualisiert (README, BEDIENUNGSANLEITUNG, Architektur)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/providers/llm/base.py

@@ -2,4 +2,9 @@ from abc import ABC, abstractmethod
 
 class LLMProvider(ABC):
     @abstractmethod
-    async def complete(self, text: str, session_id: str | None = None) -> str: ...
+    async def complete(
+        self,
+        text: str,
+        history: list[dict] | None = None,
+        session_id: str | None = None,
+    ) -> str: ...

app/providers/llm/local_openai_compatible.py

@@ -7,10 +7,17 @@ class LocalOpenAICompatibleLLM(LLMProvider):
         self.api_key = api_key
         self.model = model
 
-    async def complete(self, text: str, session_id: str | None = None) -> str:
+    async def complete(
+        self,
+        text: str,
+        history: list[dict] | None = None,
+        session_id: str | None = None,
+    ) -> str:
+        messages = list(history) if history else []
+        messages.append({"role": "user", "content": text})
         payload = {
             "model": self.model,
-            "messages": [{"role": "user", "content": text}],
+            "messages": messages,
             "temperature": 0.3,
         }
         async with httpx.AsyncClient(timeout=120) as client:

app/providers/llm/openrouter.py

@@ -49,7 +49,12 @@ class OpenRouterLLMProvider(LLMProvider):
         self.api_key = (api_key or "").strip()
         self.model = (model or "").strip()
 
-    async def complete(self, text: str, session_id: str | None = None) -> str:
+    async def complete(
+        self,
+        text: str,
+        history: list[dict] | None = None,
+        session_id: str | None = None,
+    ) -> str:
         if not self.api_key:
             raise ValueError("OPENROUTER_API_KEY is empty")
         if not self.model:
@@ -57,12 +62,14 @@ class OpenRouterLLMProvider(LLMProvider):
         if not text or not text.strip():
             raise ValueError("LLM input text is empty")
 
+        messages = [{"role": "system", "content": SYSTEM_PROMPT}]
+        if history:
+            messages.extend(history)
+        messages.append({"role": "user", "content": text.strip()})
+
         payload = {
             "model": self.model,
-            "messages": [
-                {"role": "system", "content": SYSTEM_PROMPT},
-                {"role": "user", "content": text.strip()},
-            ],
+            "messages": messages,
         }
 
         timeout = httpx.Timeout(connect=10.0, read=120.0, write=30.0, pool=10.0)