feat: session persistence, logout button, TURN HMAC fix; update docs

- Browser mode auto-rejoins saved network on reload (waste_last_network)
- Logout button (⏻) in sidebar clears session; optionally clears identity keypair
- TURN credentials now use HMAC-SHA1 of username (coturn use-auth-secret compatible)
- README: deploy scripts documented, session persistence section, serve-web.sh noted
- FUTURE.md: mark shipped items, add remaining work for daemon TURN + TUI rooms

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

web/src/store/index.ts

@@ -69,6 +69,7 @@ interface WasteState {
   rejectOffer: (peerId: string, xid: string) => void
   cancelTransfer: (peerId: string, xid: string, direction: 'recv' | 'send') => void
   createRoom: (name: string) => void
+  logout: (clearIdentity: boolean) => void
   handleEvent: (msg: IpcMessage) => void
 }
 
@@ -169,6 +170,17 @@ export const useWaste = create<WasteState>((set, get) => ({
     if (a instanceof BrowserAdapter) a.cancelTransfer(peerId, xid, direction)
   },
 
+  logout(clearIdentity) {
+    const a = get().adapter
+    if (a instanceof DaemonAdapter) a.disconnect()
+    else if (a instanceof BrowserAdapter) a.disconnect()
+    localStorage.removeItem('waste_last_network')
+    localStorage.removeItem('waste_nick')
+    localStorage.removeItem('waste_anchor_url')
+    if (clearIdentity) localStorage.removeItem('waste_seed')
+    window.location.reload()
+  },
+
   createRoom(name) {
     const netId = get().activeNetworkId
     if (!netId || !name.trim()) return