mavend: give the voice handler a CoreAPI that can serve the day plan

wireVoice runs before the tick loop exists, so it could only be handed
the bare store adapter — and that adapter answers DayPlan with "not
available via direct store API", because a day plan is assembled by the
tick loop and is not a table to read. So queryDayPlan, which the query
chain reaches for "какие у меня планы на сегодня", failed for every
caller on the deployed daemon.

main already back-patches the other direction (daemonAPI.chatFn =
handler.handleText). This is the same seam in reverse, at both wiring
sites. No recursion risk: nothing in the voice path calls api.Chat.

With the plan reachable, it recited its reminders as literal JSON. The
payload unwrapper existed but was private to the phraser, so the day
plan had its own non-unwrapping copy. One owner now, store.ReminderText,
with the phraser delegating to it.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TrVSBKe3RFDF4fGYKWYQnX

internal/phraser/phraser.go

@@ -24,7 +24,6 @@ package phraser
 
 import (
 	"context"
-	"encoding/json"
 	"fmt"
 	"strings"
 	"time"
@@ -32,6 +31,7 @@ import (
 	"github.com/kami/maven/internal/delivery"
 	"github.com/kami/maven/internal/dialogue"
 	"github.com/kami/maven/internal/loop"
+	"github.com/kami/maven/internal/store"
 )
 
 // Phraser — the seam the daemon wires. one method per delivery path (nudge
@@ -161,22 +161,11 @@ func phraseNudge(c loop.Candidate) (body, summary string) {
 	}
 }
 
-// extractReminderText — the reminder payload is raw JSON; the router's
-// reminder slot extraction owns the shape. the conventional field is "text".
-// fall back to the raw payload if it isn't JSON or lacks the field — the user
-// said it, it's the user's words.
-func extractReminderText(payload string) string {
-	var m map[string]any
-	if err := json.Unmarshal([]byte(payload), &m); err == nil {
-		if t, ok := m["text"].(string); ok && t != "" {
-			return t
-		}
-		if t, ok := m["text"]; ok {
-			return fmt.Sprintf("%v", t)
-		}
-	}
-	return strings.TrimSpace(payload)
-}
+// extractReminderText — the reminder payload is raw JSON and store.ReminderText
+// owns the unwrapping. It used to be a second copy of that logic here, which is
+// how the day plan came to recite a reminder as its literal JSON: the copies
+// were never going to be kept in step.
+func extractReminderText(payload string) string { return store.ReminderText(payload) }
 
 // humanDur — round a duration to the coarsest sensible unit for speech.
 // "4h12m" → "4 hours"; "92m" → "1h32m" → "an hour and a half". keep it simple: