Add the Recent updates sheet behind the Home bell (Feature 21)

GET /api/v1/updates lists the last 10 distinct notification events from
the outbox, newest first and one per event key whatever its channels.
POST /api/v1/updates/seen {"through": created_at} moves
household_settings.updates_seen_at forward, so /api/v1/home's
recentUpdates.unread is true only for an event stored since. The Home
bell opens a Sheet listing the updates with relative times; a row opens
its URL, and opening the sheet marks the updates seen, clearing the
grape dot optimistically and putting it back if the mark fails.

Maestro task 96e2dc3f-1f8a-4114-bcb5-e0f93c349165.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/server/home.go

@@ -1,8 +1,10 @@
 package server
 
 import (
+	"errors"
 	"log/slog"
 	"net/http"
+	"time"
 
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/home"
 )
@@ -20,3 +22,64 @@ func getHome(logger *slog.Logger, svc *home.Service) http.HandlerFunc {
 		writeJSON(w, r, logger, http.StatusOK, h)
 	}
 }
+
+// updatesBody is the GET /updates answer.
+type updatesBody struct {
+	Updates []home.Update `json:"updates"`
+}
+
+// getUpdates answers GET /updates with the Recent updates: the last
+// home.RecentLimit distinct notification events, newest first.
+func getUpdates(logger *slog.Logger, svc *home.Service) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		updates, err := svc.Updates(r.Context())
+		if err != nil {
+			logger.ErrorContext(r.Context(), "read recent updates", "error", err)
+			writeError(w, r, logger, http.StatusInternalServerError, "internal", "internal error")
+			return
+		}
+		writeJSON(w, r, logger, http.StatusOK, updatesBody{Updates: updates})
+	}
+}
+
+// maxUpdatesSeenBody bounds a POST /updates/seen request body.
+const maxUpdatesSeenBody = 1 << 10
+
+// updatesSeenRequest is the POST /updates/seen body: through is the
+// created_at of the newest update the household was shown.
+type updatesSeenRequest struct {
+	Through *string `json:"through"`
+}
+
+// postUpdatesSeen answers POST /updates/seen by recording that the
+// household has seen its updates through the body's through, and answers
+// 204. A through before the one already recorded changes nothing.
+func postUpdatesSeen(logger *slog.Logger, svc *home.Service) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		req, err := decodePatch[updatesSeenRequest](http.MaxBytesReader(w, r.Body, maxUpdatesSeenBody))
+		if err != nil {
+			writeError(w, r, logger, http.StatusBadRequest, "invalid_request", err.Error())
+			return
+		}
+		if req.Through == nil {
+			writeError(w, r, logger, http.StatusBadRequest, "invalid_request", "through: required")
+			return
+		}
+		through, err := time.Parse(time.RFC3339Nano, *req.Through)
+		if err != nil {
+			writeError(w, r, logger, http.StatusBadRequest, "invalid_request", "through: want an RFC 3339 timestamp")
+			return
+		}
+		err = svc.MarkUpdatesSeen(r.Context(), through)
+		if errors.Is(err, home.ErrSeenInFuture) {
+			writeError(w, r, logger, http.StatusBadRequest, "invalid_request", "through: must not be after now")
+			return
+		}
+		if err != nil {
+			logger.ErrorContext(r.Context(), "mark recent updates seen", "error", err)
+			writeError(w, r, logger, http.StatusInternalServerError, "internal", "internal error")
+			return
+		}
+		w.WriteHeader(http.StatusNoContent)
+	}
+}