feat: prompt SpaceJoin when opening unjoined space via direct link

src/routes/spaces/[relay]/+layout.svelte

@@ -1,15 +1,18 @@
 <script lang="ts">
   import type {Snippet} from "svelte"
+  import {get} from "svelte/store"
   import {page} from "$app/stores"
   import {once} from "@welshman/lib"
+  import {pubkey} from "@welshman/app"
   import Page from "@lib/components/Page.svelte"
   import SecondaryNav from "@lib/components/SecondaryNav.svelte"
   import SpaceMenu from "@app/components/SpaceMenu.svelte"
   import SpaceAuthError from "@app/components/SpaceAuthError.svelte"
   import SpaceTrustRelay from "@app/components/SpaceTrustRelay.svelte"
+  import SpaceJoin from "@app/components/SpaceJoin.svelte"
   import {pushModal} from "@app/util/modal"
   import {makeSpacePath} from "@app/util/routes"
-  import {decodeRelay, relaysPendingTrust} from "@app/core/state"
+  import {decodeRelay, relaysPendingTrust, userSpaceUrls, loadUserGroupList} from "@app/core/state"
   import {deriveRelayAuthError} from "@app/core/commands"
 
   type Props = {
@@ -28,6 +31,8 @@
 
   const showPendingTrust = once(() => pushModal(SpaceTrustRelay, {url}, {noEscape: true}))
 
+  const joinPrompted = new Set<string>()
+
   // Watch for relay errors and notify the user
   $effect(() => {
     if ($authError) {
@@ -36,6 +41,49 @@
       showPendingTrust()
     }
   })
+
+  // Direct links skip Discover — prompt to join when relay is not in the user's space list.
+  $effect(() => {
+    const spaceUrl = url
+    const currentPubkey = get(pubkey)
+
+    if (!currentPubkey) {
+      return
+    }
+
+    if ($userSpaceUrls.includes(spaceUrl) || $authError || $relaysPendingTrust.includes(spaceUrl)) {
+      return
+    }
+
+    let cancelled = false
+
+    void loadUserGroupList().then(() => {
+      if (cancelled) {
+        return
+      }
+
+      if (get(pubkey) !== currentPubkey) {
+        return
+      }
+
+      if (
+        get(userSpaceUrls).includes(spaceUrl) ||
+        get(authError) ||
+        get(relaysPendingTrust).includes(spaceUrl) ||
+        joinPrompted.has(spaceUrl)
+      ) {
+        return
+      }
+
+      joinPrompted.add(spaceUrl)
+      pushModal(SpaceJoin, {url: spaceUrl})
+    })
+
+    return () => {
+      cancelled = true
+      joinPrompted.delete(spaceUrl)
+    }
+  })
 </script>
 
 {#if $page.url.pathname === makeSpacePath(url)}