Email digest: GET-first restore on boot so reloads stop re-sending confirmations

Mail.sync's boot reconcile now GETs the existing subscription (NIP-98
auth) before deciding what to do. When a subscription already exists for
the pubkey with the same email and frequency, its key/callback are
restored in memory and the PUT is skipped entirely. Only a matching
subscription missing the requested params triggers a PUT, so a page
refresh of an unconfirmed address no longer makes mailship re-send a
confirmation email (previously each reload sent one).

src/app/mail/index.ts

@@ -150,6 +150,42 @@ export class MailNotifications {
     return this._register
   }
 
+  // Fetch the existing subscription for this pubkey (if any) without creating
+  // or changing anything. Used at boot to restore state instead of re-PUTting,
+  // which would otherwise re-send a confirmation email for an unconfirmed
+  // address on every reload.
+  async lookup(): Promise<
+    | {
+        key: string
+        callback: string
+        email: string
+        frequency: string
+        confirmed: boolean
+      }
+    | undefined
+  > {
+    const $signer = app.get().user?.signer
+    if (!$signer || !EMAIL_NOTIFICATION_SERVER) return undefined
+
+    try {
+      const authEvent = await $signer.sign(
+        await makeHttpAuth(buildUrl(EMAIL_NOTIFICATION_SERVER, "subscription", "email"), "GET"),
+      )
+      const authHeader = makeHttpAuthHeader(authEvent)
+
+      const res = await fetch(buildUrl(EMAIL_NOTIFICATION_SERVER, "subscription", "email"), {
+        method: "GET",
+        headers: {Authorization: authHeader},
+      })
+
+      if (!res.ok) return undefined
+
+      return await res.json()
+    } catch {
+      return undefined
+    }
+  }
+
   async unregister() {
     const {key} = emailNotificationState.get()
     if (!key) return
@@ -231,8 +267,27 @@ export class MailNotifications {
 
       reconciledPubkey = $pubkey
 
+      // GET-first: if a subscription already exists for this pubkey with the
+      // same email and cadence, restore its state (key/callback) instead of
+      // PUTting. A PUT here would make mailship re-send a confirmation email
+      // for an unconfirmed address on every app reload. Only register when
+      // there's nothing to restore or the settings changed.
+      const existing = await this.lookup()
+
       try {
-        await this.register(emailAddress, emailFrequency)
+        if (!existing) {
+          await this.register(emailAddress, emailFrequency)
+        } else if (existing.email !== emailAddress || existing.frequency !== emailFrequency) {
+          await this.register(emailAddress, emailFrequency)
+        } else {
+          emailNotificationState.set({
+            key: existing.key,
+            callback: existing.callback,
+            email: existing.email,
+            frequency: existing.frequency,
+            error: undefined,
+          })
+        }
       } catch {
         return
       }