backend: Pydantic response_models für 5 GET-Endpoints hinzufügen

- health.py: HealthResponse
- eigenleben.py: EigenlebenOverviewResponse + SkillTextResponse
- chronik.py: ChronikResponse + ChronikItem
- wissen.py: WissenListResponse + WissenFileResponse
- reminders.py: ReminderListResponse + ReminderOut

py_compile bestanden, /docs zeigt neue Schemata.
Response-Payloads unverändert — nur Typisierung hinzugefügt.

backend/routers/wissen.py

@@ -6,6 +6,8 @@ import os
 import time
 from pathlib import Path
 
+from pydantic import BaseModel
+
 from fastapi import APIRouter, HTTPException
 
 router = APIRouter(prefix="/api")
@@ -30,7 +32,27 @@ def _title_of(p: Path) -> str:
     return p.stem
 
 
-@router.get("/wissen")
+class VaultFile(BaseModel):
+    path: str
+    name: str
+    dir: str
+    title: str
+    mtime: float
+    neu: bool
+
+
+class WissenListResponse(BaseModel):
+    available: bool
+    files: list[VaultFile]
+
+
+class WissenFileResponse(BaseModel):
+    path: str
+    content: str
+    mtime: float
+
+
+@router.get("/wissen", response_model=WissenListResponse)
 def list_vault() -> dict:
     """Alle Markdown-Notizen des Vaults (relativer Pfad, Titel, Ordner, Alter)."""
     if not _available():
@@ -54,7 +76,7 @@ def list_vault() -> dict:
     return {"available": True, "files": files}
 
 
-@router.get("/wissen/datei")
+@router.get("/wissen/datei", response_model=WissenFileResponse)
 def read_file(pfad: str) -> dict:
     """Inhalt einer Vault-Notiz — Traversal hart geblockt (resolve + is_relative_to)."""
     if not _available():