Add initial documentation and structure for DorkNet project

- Create README.md for project overview and setup instructions
- Add admin-ui/README.md for admin UI details and development setup
- Introduce client-mod/README.md explaining the MelonLoader mod functionality
- Establish docker/README.md for Docker setup and configuration
- Create docs/README.md to index project documentation
- Implement advanced-setup.md for Docker stack configuration
- Document architecture in architecture.md
- Provide easy-setup.md for hosting instructions
- Add FAQ.md for common questions and legal considerations
- Create joining-a-server.md for player connection instructions
- Establish troubleshooting.md for common issues and resolutions
- Introduce easy-app/README.md for the unified desktop application
- Add server/README.md for ASP.NET Core backend details
- Document tools/README.md for CLI helper scripts

docs/troubleshooting.md

@@ -0,0 +1,96 @@
+# Troubleshooting
+
+If your symptom isn't here, check [the FAQ](faq.md) and then open an
+issue with: your OS, DorkNet version, server log (Settings → Send logs
+to clipboard), and the exact steps that triggered the problem.
+
+## Client / patcher
+
+### "Signature verification failed" on launch
+
+The image-signing public key baked into the patched `global-metadata.dat`
+doesn't match the private key on the server. Repair from the Patch tab —
+this re-fetches the server's current pubkey before patching.
+
+### "Check your internet connection" loop at startup
+
+The watch can't reach the server URL. Verify:
+1. The host string in `dorknet-clientmod.json` matches the server's
+   public URL (tunnel URL for Easy mode).
+2. The server responds to `https://<host>/healthz` with `200 OK` from
+   the same machine the client runs on.
+3. No corporate proxy / DNS filter is intercepting `*.trycloudflare.com`.
+
+### Black screen after the loading bar fills
+
+The watch authenticated, joined Photon, but couldn't download the room
+data blob. Look in MelonLoader's `Latest.log` for
+`[DownloadRoomDataBlobCoroutine]` lines — the URL there tells you which
+asset the server failed to serve.
+
+### Save doesn't persist, MakerPen objects disappear after reload
+
+Known issue with stale `LocalRoomScene.DataBlobName`. The client mod's
+`SetRoomDataBlobName_Prefix` hijack should handle this — verify it's
+firing in MelonLoader's log. If not, the mod failed to load; check that
+`Mods\DorkNet.ClientMod.dll` is present and not blocked by Windows.
+
+## Server
+
+### `[boot] migrations failed`
+
+The schema patch SQL errored. Most likely cause: an existing column whose
+type doesn't match what we're trying to add. Look at the exact failure
+in the log; if it's a Postgres `cannot alter type` error, the prior
+column type needs a manual migration before DorkNet starts.
+
+### Photon CustomAuth returns 401
+
+Either:
+- The Photon AppId in `appsettings` doesn't match the AppId baked into
+  the patched client. They MUST match.
+- The user logging in doesn't have a row in the `Players` table — the
+  auth flow expects `userid` to be a real account.
+
+### Room chat doesn't send
+
+Run the client with `SaveDebugMod` enabled (or watch MelonLoader's log)
+and look for the `[chat-trace]` lines. The pipeline is:
+
+```
+SendChatEmote → RemoveInvalidCharactersFromMessage → PurifyString HTTP
+              → ProcessNewChatMessageReceived → Photon RPC
+```
+
+If any trace line is missing, that's where it died. The two most common
+fixes:
+- `[chat-fix] CanLocalPlayerChat returned false`: the account is flagged
+  as a Junior with chat disabled. Force-true via the client mod (default
+  behavior) or fix it server-side in admin.
+- `Received malformed RecNet response`: the `/api/sanitize/v1` endpoint
+  returned the wrong shape. Should be a bare JSON-quoted string. See
+  `SanitizeController.cs`.
+
+## Easy app
+
+### "Cloudflared exited unexpectedly"
+
+The bundled `cloudflared.exe` couldn't start. Most likely a Windows
+Defender false-positive — check Defender's quarantine. If you find a
+cleaner alternative tunnel provider, open an issue; we've been looking
+for one.
+
+### Patch button is greyed out
+
+DorkNet didn't find a Rec Room install at the path you selected. Make
+sure you pointed at the *folder* containing `Recroom_Release.exe`, not
+the exe itself, and that `Recroom_Release_Data/` exists alongside.
+
+### Mode switch lost my server data
+
+Switching from Host mode → Join mode preserves the SQLite database; it
+just stops auto-starting the server. Switch back to Host mode and your
+players / rooms / images are still there.
+
+If the data really is gone, check `%APPDATA%\DorkNet\dorknet.db` — that
+file is the entire host-side state, easy to copy elsewhere as a backup.