Mobile notifications for iOS (#210)

* mobile: wire notification registration and listener

* implement backend components for push notifications

* refactor: agentic comment cleanup

* docs: use proper module name for particle processor

* set required env variables for push notifications

* bump version

* fix: always upsert push token on mobile start

* Revert "fix: always upsert push token on mobile start"

This reverts commit 90ff18a788.

* send push notifications regardless of online status

go/internal/handler/push_token.go

@@ -0,0 +1,83 @@
+package handler
+
+import (
+	"encoding/json"
+	"errors"
+	"log/slog"
+	"net/http"
+
+	"github.com/flowy-live/llink/internal/human/pushnotify"
+	"github.com/flowy-live/llink/internal/middleware"
+)
+
+type RegisterPushTokenRequest struct {
+	Token      string `json:"token"`
+	Platform   string `json:"platform"`
+	AppVersion string `json:"app_version"`
+}
+
+type UnregisterPushTokenRequest struct {
+	Token string `json:"token"`
+}
+
+// RegisterPushToken upserts an Expo token; ON CONFLICT transparently re-binds
+// a token to a new human after a device-level account switch.
+func (h *Handler) RegisterPushToken(w http.ResponseWriter, r *http.Request) {
+	humanId, ok := middleware.HumanIdFromContext(r.Context())
+	if !ok {
+		http.Error(w, "unauthorized", http.StatusUnauthorized)
+		return
+	}
+
+	var req RegisterPushTokenRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		http.Error(w, "invalid request body", http.StatusBadRequest)
+		return
+	}
+
+	err := h.pushTokenSvc.Register(r.Context(), humanId, pushnotify.RegisterInput{
+		Token:      req.Token,
+		Platform:   pushnotify.Platform(req.Platform),
+		AppVersion: req.AppVersion,
+	})
+	if err != nil {
+		if errors.Is(err, pushnotify.ErrInvalidPlatform) || errors.Is(err, pushnotify.ErrInvalidToken) {
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
+		slog.Error("failed to register push token", "error", err, "humanId", humanId)
+		http.Error(w, "internal server error", http.StatusInternalServerError)
+		return
+	}
+
+	w.WriteHeader(http.StatusNoContent)
+}
+
+// UnregisterPushToken returns 204 whether or not the token existed (idempotent).
+func (h *Handler) UnregisterPushToken(w http.ResponseWriter, r *http.Request) {
+	humanId, ok := middleware.HumanIdFromContext(r.Context())
+	if !ok {
+		http.Error(w, "unauthorized", http.StatusUnauthorized)
+		return
+	}
+
+	var req UnregisterPushTokenRequest
+	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
+		http.Error(w, "invalid request body", http.StatusBadRequest)
+		return
+	}
+
+	if req.Token == "" {
+		http.Error(w, "token is required", http.StatusBadRequest)
+		return
+	}
+
+	err := h.pushTokenSvc.Unregister(r.Context(), humanId, req.Token)
+	if err != nil && !errors.Is(err, pushnotify.ErrNotFound) {
+		slog.Error("failed to unregister push token", "error", err, "humanId", humanId)
+		http.Error(w, "internal server error", http.StatusInternalServerError)
+		return
+	}
+
+	w.WriteHeader(http.StatusNoContent)
+}