fix: signer-scoped DirectV1 routing (#162)

Core is no longer account-aware: the client resolves an account address
to signer ids via the account directory, and the signer's verifying-key
hex serves as registry key, inbox subscription, and Welcome routing
target end to end. The MLS credential stays the full id().

- GroupV2 reads the de-mls member id from the fetched key package and
  maps it to the signer id the welcome is delivered to.
- All account machinery (directory trait, bundle codec, resolution)
  moves out of core into logos-account; the RegistrationService
  supertrait and Core::account_directory() are gone, and the client
  holds its own directory handle.
- The account exposes functionality, never a signer: add_delegate_signer
  does the lamport upsert and signs internally.
- Every client acts for an account (ChatClientBuilder::new(account)).
  DelegateSigner is a pure keypair; the client composes the wire
  credential from the signer and the account, so the association is
  client state. addr() is the account address.
- resolve_device_ids fails fast (NotAnAccountKey / NoDeviceBundle /
  Directory) instead of falling back to treating an unresolved address
  as a signer id. LogosChatClient::open and chat-cli mint and publish a
  dev account each launch.
- EphemeralRegistry keys key packages by hex pubkey like HttpRegistry.

Supersedes #155 (routing_id).

bin/chat-cli/src/ui.rs

@@ -16,7 +16,7 @@ use ratatui::{
     widgets::{Block, Borders, List, ListItem, Paragraph, Wrap},
 };
 
-use logos_chat::{ChatStore, IdentityProvider, RegistrationService, Transport};
+use logos_chat::{AccountDirectory, ChatStore, RegistrationService, Transport};
 
 use crate::app::ChatApp;
 
@@ -38,11 +38,10 @@ pub fn restore() -> io::Result<()> {
 }
 
 /// Draw the UI.
-pub fn draw<I, D, R, S>(frame: &mut Frame, app: &ChatApp<I, D, R, S>)
+pub fn draw<D, R, S>(frame: &mut Frame, app: &ChatApp<D, R, S>)
 where
-    I: IdentityProvider + Send + 'static,
     D: Transport + Send + 'static,
-    R: RegistrationService + Send + 'static,
+    R: RegistrationService + AccountDirectory + Clone + Send + 'static,
     S: ChatStore + Send + 'static,
 {
     let chunks = Layout::default()
@@ -61,11 +60,10 @@ where
     draw_status(frame, app, chunks[3]);
 }
 
-fn draw_header<I, D, R, S>(frame: &mut Frame, app: &ChatApp<I, D, R, S>, area: Rect)
+fn draw_header<D, R, S>(frame: &mut Frame, app: &ChatApp<D, R, S>, area: Rect)
 where
-    I: IdentityProvider + Send + 'static,
     D: Transport + Send + 'static,
-    R: RegistrationService + Send + 'static,
+    R: RegistrationService + AccountDirectory + Clone + Send + 'static,
     S: ChatStore + Send + 'static,
 {
     let title = match app.current_session() {
@@ -90,11 +88,10 @@ where
     frame.render_widget(header, area);
 }
 
-fn draw_messages<I, D, R, S>(frame: &mut Frame, app: &ChatApp<I, D, R, S>, area: Rect)
+fn draw_messages<D, R, S>(frame: &mut Frame, app: &ChatApp<D, R, S>, area: Rect)
 where
-    I: IdentityProvider + Send + 'static,
     D: Transport + Send + 'static,
-    R: RegistrationService + Send + 'static,
+    R: RegistrationService + AccountDirectory + Clone + Send + 'static,
     S: ChatStore + Send + 'static,
 {
     let remote_name = app
@@ -182,11 +179,10 @@ where
     frame.render_stateful_widget(messages_widget, area, &mut list_state);
 }
 
-fn draw_input<I, D, R, S>(frame: &mut Frame, app: &ChatApp<I, D, R, S>, area: Rect)
+fn draw_input<D, R, S>(frame: &mut Frame, app: &ChatApp<D, R, S>, area: Rect)
 where
-    I: IdentityProvider + Send + 'static,
     D: Transport + Send + 'static,
-    R: RegistrationService + Send + 'static,
+    R: RegistrationService + AccountDirectory + Clone + Send + 'static,
     S: ChatStore + Send + 'static,
 {
     // Inner width: area minus borders (2).
@@ -215,11 +211,10 @@ where
     frame.set_cursor_position((cursor_x, area.y + 1));
 }
 
-fn draw_status<I, D, R, S>(frame: &mut Frame, app: &ChatApp<I, D, R, S>, area: Rect)
+fn draw_status<D, R, S>(frame: &mut Frame, app: &ChatApp<D, R, S>, area: Rect)
 where
-    I: IdentityProvider + Send + 'static,
     D: Transport + Send + 'static,
-    R: RegistrationService + Send + 'static,
+    R: RegistrationService + AccountDirectory + Clone + Send + 'static,
     S: ChatStore + Send + 'static,
 {
     let status = Paragraph::new(app.status.as_str())
@@ -231,11 +226,10 @@ where
 }
 
 /// Handle keyboard events.
-pub fn handle_events<I, D, R, S>(app: &mut ChatApp<I, D, R, S>) -> io::Result<bool>
+pub fn handle_events<D, R, S>(app: &mut ChatApp<D, R, S>) -> io::Result<bool>
 where
-    I: IdentityProvider + Send + 'static,
     D: Transport + Send + 'static,
-    R: RegistrationService + Send + 'static,
+    R: RegistrationService + AccountDirectory + Clone + Send + 'static,
     S: ChatStore + Send + 'static,
 {
     // Poll for events with a short timeout to allow checking incoming messages