Show peers immediately on discovery, before DataChannel opens

Emit peer_connected + peer_status(connecting) as soon as a PeerConn is
created, so peers appear in the sidebar even if ICE is still negotiating
or ultimately fails. The alias updates in-place once the DataChannel hello
arrives with the real nick.

Fixes: mobile/CGNAT peers being completely invisible when STUN hole
punching fails — they now show with a connecting/failed dot instead of
not appearing at all.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web/src/adapter/browser.ts

@@ -707,6 +707,7 @@ export class BrowserAdapter {
     const peer = new PeerConn(this.identity, this.sig!, pid,
       (ev, data) => this._onPeerEvent(ev, data), this.identity.nick, this.sharedFiles)
     this.peers.set(pid, peer)
+    this._emitDiscovered(pid)
     await peer.startOffer()
   }
 
@@ -716,6 +717,7 @@ export class BrowserAdapter {
     if (!peer || peer.pc.connectionState === 'failed' || peer.pc.connectionState === 'closed') {
       peer = new PeerConn(this.identity, this.sig!, from,
         (ev, data) => this._onPeerEvent(ev, data), this.identity.nick, this.sharedFiles)
+      this._emitDiscovered(from)
       this.peers.set(from, peer)
     }
     await peer.onBox(box)
@@ -810,6 +812,18 @@ export class BrowserAdapter {
     }
   }
 
+  private _emitDiscovered(pid: string) {
+    this.emit({
+      type: 'peer_connected',
+      peer: { id: pid, alias: pid.slice(0, 8), public_key: pid, created_at: new Date().toISOString() },
+    })
+    this.emit({
+      type: 'peer_status',
+      peer_id: pid as unknown as import('../types').PeerID,
+      conn_state: 'connecting',
+    })
+  }
+
   setSharedFiles(files: Map<string, File>) {
     this.sharedFiles = files
     this.peers.forEach(p => { p.share = files })