feat(invite): privacy + expiry + trust gate + network CTA polish

[8144225309]

Summary

Four invite-flow gaps surfaced during visual review of PR #53 (manual-connect modal). Each is small and self-contained.

1. inviteUrl.ts — expiry codec

• Adds optional expires=<unix-ts> URL param
• New parseInviteUrlDetailed(url) returns {invite, error: 'malformed' | 'expired' | null} so callers can distinguish bad-URL from stale-invite for UX messaging
• parseInviteUrl kept as thin wrapper (backwards compat)

2. InviteModal (LSP-host side)

• Expiry dropdown — Never / 1d / 1w / 30d / 90d. Embeds expires only when set; existing permanent-invite behavior is the default.
• Tor-preferred toggle — when both .onion and ipv4 are advertised, default to broadcasting the .onion so casual invite-sharing doesn't leak the operator's public IP. Operator can flip back.
• Privacy warning Alert when the chosen address is a public-routable IP (RFC1918 + loopback + .onion suppressed). Surfaces the leaked address and points the operator at the tor toggle.

3. AcceptInviteModal (client side)

• Uses parseInviteUrlDetailed so expired invites get a clear "ask the LSP operator for a fresh one" message instead of generic "malformed URL".
• Trust gate — if the parsed address is public-routable, render a warning Alert with an "I trust the source of this invite" checkbox. The Send-join-request button stays disabled until ticked.
• Tor info note when the invite uses an .onion address (positive feedback).

4. ConnectList — profile-switch CTA

When the active node's network has no coordinator binding (common on regtest / sandbox profiles), the empty-state row now lists the user's other profiles that ARE covered and offers one-click switch buttons. Reuses the same NodesService.switchNode flow as NodePicker (clear stores → switch → refetch).

Test plan

• Build / eslint / tests green in CI
• Visual sweep against demo wallet after deploy:
  • Invite modal renders expiry dropdown
  • Invite modal renders tor toggle when both .onion + ipv4 present
  • Invite modal renders privacy warning when address resolves to public IP
  • Accept modal shows "expired" error for stale invites
  • Accept modal shows trust gate + disables Send for public IPs
  • Connect page empty state on regtest profile shows switch-to-testnet4 button and the switch fires