feat(ai-services): add Vietnamese NLP pipeline for property description analysis

Implement auto-tagging (amenities, location features, condition/legal),
content quality scoring with moderation integration, and FastAPI endpoints
for single and batch text analysis. Uses underthesea for Vietnamese
tokenization/POS when available, with regex fallback.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

libs/ai-services/app/routers/nlp.py

@@ -0,0 +1,27 @@
+from fastapi import APIRouter
+
+from app.models.nlp import (
+    BatchAnalyzeRequest,
+    BatchAnalyzeResponse,
+    NLPAnalyzeRequest,
+    NLPAnalyzeResponse,
+)
+from app.services.nlp_service import nlp_service
+
+router = APIRouter(prefix="/nlp", tags=["NLP"])
+
+
+@router.post("/analyze", response_model=NLPAnalyzeResponse)
+def analyze(req: NLPAnalyzeRequest) -> NLPAnalyzeResponse:
+    """Analyze Vietnamese property description: auto-tag, quality score, tokenize."""
+    return nlp_service.analyze(req)
+
+
+@router.post("/batch-analyze", response_model=BatchAnalyzeResponse)
+def batch_analyze(req: BatchAnalyzeRequest) -> BatchAnalyzeResponse:
+    """Batch analyze multiple property descriptions."""
+    results = [
+        nlp_service.analyze(NLPAnalyzeRequest(text=t, include_moderation=req.include_moderation))
+        for t in req.texts
+    ]
+    return BatchAnalyzeResponse(results=results)