feat(dashboard): integrate link suggestions and predictive links into UI

- FastAPI: parse_engram now includes link_suggestions and predictive_links from metadata
- FastAPI: add POST /api/links/accept to create links from suggestions
- Dashboard: new renderCardsWithSuggestions() displays suggestions in each card
- Dashboard: acceptLink() function handles click-to-link
- Dashboard: loadCards() calls renderCardsWithSuggestions()
- Systemd: remove DirectoryNotEmpty from ingest path unit (already present)

Refs: #25 #27

fastapi_app.py

@@ -63,7 +63,7 @@ def parse_engram(row: sqlite3.Row) -> dict:
             verdict = "confirmed_false"
         else:
             verdict = "unknown"
-    return {
+    result = {
         "id": row["id"],
         "content": row["content"],
         "confidence": meta.get("confidence", 0.0),
@@ -81,6 +81,12 @@ def parse_engram(row: sqlite3.Row) -> dict:
         "access_count": meta.get("access_count", 0),
         "grounding": meta.get("grounding", 0),
     }
+    # Vorschläge aus metadata
+    if "link_suggestions" in meta:
+        result["link_suggestions"] = meta["link_suggestions"]
+    if "predictive_links" in meta:
+        result["predictive_links"] = meta["predictive_links"]
+    return result
 
 
 def _now_iso() -> str:
@@ -902,6 +908,31 @@ def api_refresh(engram_id: str):
     return {"success": True, "new_confidence": round(conf, 2)}
 
 
+@app.post("/api/links/accept")
+def api_accept_link(from_id: str = Form(...), to_id: str = Form(...)):
+    """Erstelle einen Link zwischen zwei Engrammen (aus Vorschlag)."""
+    conn = get_db()
+    c = conn.cursor()
+    # Prüfe Existenz beider Engramme
+    for eid in (from_id, to_id):
+        if not c.execute("SELECT 1 FROM engrams WHERE id = ?", (eid,)).fetchone():
+            conn.close()
+            return JSONResponse({"error": f"Engram {eid} not found"}, status_code=404)
+    # Vermeide Duplikate
+    c.execute("SELECT 1 FROM engrams_links WHERE from_id = ? AND to_id = ?", (from_id, to_id))
+    if c.fetchone():
+        conn.close()
+        return {"ok": True, "message": "link already exists"}
+    # Link erstellen
+    c.execute(
+        "INSERT INTO engrams_links (from_id, to_id) VALUES (?, ?)",
+        (from_id, to_id)
+    )
+    conn.commit()
+    conn.close()
+    return {"ok": True}
+
+
 @app.post("/api/engrams")
 def api_create_engram(content: str = Form(...), tags: str = Form(""), source: str = Form("web")):
     engram_id = f"web-{datetime.now(timezone.utc).strftime('%Y%m%d-%H%M%S-%f')[:20]}"