phraser: move errEmptyResponse next to its only caller (V-397)

It sat in world.go, which is about the workstation model; it is a phrasing
error and belongs in llmphraser.go. Also trims the PhraseQuery doc.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

internal/phraser/llmphraser.go

@@ -5,6 +5,7 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"log"
@@ -26,6 +27,11 @@ import (
 
 var listenRE = regexp.MustCompile(`listening on (https?://\S+)`)
 
+// errEmptyResponse — the server answered and said nothing. Separate from a
+// transport failure: the model is up and produced no tokens, which is still not
+// an answer and must not score as one.
+var errEmptyResponse = errors.New("phraser: empty response from the model")
+
 type LLMPhraser struct {
 	cfg    Config
 	client *http.Client
@@ -428,10 +434,10 @@ func (p *LLMPhraser) PhraseNudge(ctx context.Context, c loop.Candidate) (deliver
 }
 
 // PhraseQuery prompts the LLM with the user's utterance and matching notes to
-// compose a natural answer. On any LLM error it returns BOTH the fallback text
+// compose a natural answer. On any LLM error it returns the fallback text —
-// ("вот что я нашла: <notes>", or "не знаю." with no notes) AND the error, so a
+// "вот что я нашла: <notes>", or "не знаю." with no notes — and the error
-// caller that wants to keep the turn alive uses the text and a caller that is
+// together. The daemon uses the text and keeps the turn alive; a caller that is
-// measuring counts the failure. Until Vikunja #397 the error was swallowed and a
+// measuring counts the failure. Until Vikunja #397 the error was dropped, so a
 // dead server scored as bad phrasing.
 func (p *LLMPhraser) PhraseQuery(ctx context.Context, utterance string, notes []string) (string, error) {
 	// Blank sources are no sources. A caller that hands over one empty string —

internal/phraser/world.go

@@ -37,11 +37,6 @@ type Remote interface {
 // (docs/evals/2026-08-02-workstation-gemma4-12b.md).
 var ErrNoWorldModel = errors.New("phraser: no world model available")
 
-// errEmptyResponse — the server answered and said nothing. A separate error from
-// a transport failure because it means the model is up and produced no tokens,
-// which is still not an answer and must not score as one.
-var errEmptyResponse = errors.New("phraser: empty response from the model")
-
 // chatTemperature — what the phraser's own transport has always sampled at.
 // Named so the remote path cannot drift from it silently. Whether 0.7 is right
 // at all is Vikunja #402, and answering that here would hide a phrasing change