Wire voice-tapped facts into entity resolution; fix phraser model config

WriteFactReq gains an optional Subject field (empty = old behavior,
no CoreAPI signature change) and the IntentFact handler now passes the
fact's key as its resolution subject, so voice-tapped facts flow into
the Vikunja #279 enrichment queue automatically.

Also: deploy/mavend.json's phraser was pointed at a 4B model with
n_gpu_layers=99, which OOM'd under memory pressure and left a zombie
llama-server child. Swapped to the 2B Qwen model matching the intended
resident-model size, keeping GPU offload.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018ghELqYhZNLub2TXGMazqA

cmd/mavend/voice.go

@@ -550,6 +550,13 @@ func (h *reactiveHandler) applyAction(ctx context.Context, dec router.Decision)
 			Value:      dec.Slots.Value,
 			Source:     "tap:voice",
 			Confidence: 1.0,
+			// Subject: the key doubles as the entity-resolution candidate —
+			// a voice-tapped fact's key is usually the thing/person it's
+			// about ("espresso_machine", "kate"), so queueing it for Nexus
+			// resolution costs one async lookup and is a no-op (not_found)
+			// for the abstract self-state keys (mood, water) that aren't
+			// entities at all.
+			Subject: dec.Slots.Key,
 		}
 		factID, err := h.api.WriteFact(ctx, req)
 		if err != nil {