Localtunnel hosting + admin panel + AppData db

- Default hosting mode is now Localtunnel — public *.loca.lt URL,
  no account, auto-fetched on first run. Replaces the prototyped
  Tailscale mode.
- Tailscale code purged from launcher + CLI; docs swapped to
  Localtunnel throughout (easy-setup, joining-a-server, server-cli,
  troubleshooting, faq, READMEs).
- Launcher sidebar gains an Open admin panel button — opens
  https://admin.<apex> in the browser once the server is live.
- SQLite db moves to %APPDATA%\DorkNet\dorknet.db (server reads
  Database__SqlitePath env var, launcher passes it). Existing dbs
  under <serverDir>\data\ are migrated on first run.
- CLI Program.cs: --mode default flips from tailscale to localtunnel;
  csproj links in LocaltunnelTunnel + LocaltunnelInstaller.
- New Backend files: LauncherNameServer, LocaltunnelInstaller,
  LocaltunnelTunnel, SingleOriginServiceMap.
- .gitignore: exclude installer/out/.

docs/faq.md

@@ -80,11 +80,16 @@ the server config; the client mod handles the rest.
 ### My friend can't connect
 
 Most common causes, in order:
-1. **Tunnel URL stale.** Cloudflare Quick Tunnels rotate the URL on each
-   restart. Re-share the join code.
+1. **Stale join code.** Localtunnel hands out a fresh `*.loca.lt` URL
+   on every host restart. Hit Start hosting, copy the new join code
+   from the launcher, send the new code to your friend.
 2. **Photon region mismatch.** Both clients must use the same Photon
    region — set in Settings.
-3. **Friend didn't patch.** They need to run the Patch tab pointed at
-   their own Rec Room install, with your join code.
+3. **Friend didn't patch.** They need to open the Join view in their
+   launcher, paste your join code, and click APPLY PATCH before
+   launching Rec Room.
+4. **Localtunnel interstitial.** First time a joiner's machine hits a
+   given `*.loca.lt` URL, Localtunnel may show a one-time "Click to
+   Continue" page. Open the URL once in any browser and retry.
 4. **Junior account / accessibility settings.** Server settings → relax
    moderation gates if friends are on accounts with parental controls.