fix(nip46): make forgetting a client complete and immediate

Clearing a connected client on logout had two gaps:

- The user-facing "Forget this app" button only revoked the permission ledger;
  it never cleared the NIP-46 client store, so a forgotten app's metadata and
  relays lingered and were re-recovered on the next restart. Route NIP-46
  coordinates through the host's new forgetClient() so the store is cleared too.
- Neither logout path stopped the RUNNING session from listening on the app's
  relays — only the next restart picked up the change. extraRelays is now a live
  projection of the client store (recomputed on connect, on start, and on
  disconnect via a new onDisconnected hook), so a forgotten app's relays are
  dropped immediately.

onLogout and the UI Forget now share one authorizer.forget() path (revoke grant
+ clear store + clear throttle entry + signal the host), so client-initiated and
user-initiated disconnects behave identically. Adds tests for both.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015FHr2mu5SiHwYNR7evYUuF

commons/src/commonMain/kotlin/com/vitorpamplona/amethyst/commons/connectedApps/nip46/Nip46PermissionAuthorizer.kt

@@ -77,6 +77,12 @@ class Nip46PermissionAuthorizer(
     val onConnected: (suspend (clientPubKey: HexKey, request: BunkerRequestConnect) -> Unit)? = null,
     /** Persisted client metadata/relays; cleared on logout so a disconnected app leaves nothing behind. */
     val clientStore: Nip46ClientStore? = null,
+    /**
+     * Invoked after a client is fully forgotten ([onLogout]/[forget]) so the host can react in the
+     * running session — e.g. stop listening on relays that only that client used, instead of waiting
+     * for the next restart.
+     */
+    val onDisconnected: (suspend (clientPubKey: HexKey) -> Unit)? = null,
 ) : Nip46RequestAuthorizer {
     // A high-throughput client can authorize many signs per second; last-used is display-only,
     // so coalesce the DataStore write to at most one per client per LAST_USED_THROTTLE_SECS
@@ -136,12 +142,20 @@ class Nip46PermissionAuthorizer(
         return allowed
     }
 
-    override suspend fun onLogout(clientPubKey: HexKey) {
-        // The client asked to disconnect — drop its standing grant (so it must pair again) and its
-        // persisted metadata/relays (so we stop listening on its relays after the next restart).
+    override suspend fun onLogout(clientPubKey: HexKey) = forget(clientPubKey)
+
+    /**
+     * Fully disconnects [clientPubKey], from either the client's `logout` request or the user's
+     * "Forget" action: drops its standing grant (so it must pair again), its persisted metadata/relays,
+     * and its in-memory throttle entry, then signals [onDisconnected] so the running session can stop
+     * listening on relays that only this client used.
+     */
+    suspend fun forget(clientPubKey: HexKey) {
         val coordinate = coordinateFor(clientPubKey)
         ledger.revokeAll(coordinate)
         clientStore?.remove(coordinate)
+        throttleLock.withLock { lastUsedThrottle.remove(coordinate) }
+        onDisconnected?.invoke(clientPubKey)
     }
 
     companion object {