launcher: v0.1 — PhotinoNET shell + multi-version orchestration

Single-download .NET 9 self-contained launcher for hosting / joining
DorkNet servers. Reads versions.json from main to discover supported
client builds, fetches the matching server binary + client patcher
from GitHub Releases per branch, manages the server subprocess +
Cloudflare quick-tunnel, and wraps it all in a PhotinoNET window.

Code layout:
- Program.cs           PhotinoNET window + message bridge bootstrap
- Backend/             AppPaths, AppState, VersionsManifest,
                       ReleaseDownloader, ServerProcess, ClientPatcher,
                       Tunnel, RecRoomPicker, JoinCode, MessageBridge
- ui/                  index.html + style.css + app.js (no build step)
- RELEASES.md          GitHub Releases artifact contract per-version
                       branches must publish to

Per-version branches need to ship two release assets per tag:
- dorknet-server-{version_key}-win-x64.zip
- dorknet-clientpatch-{version_key}.zip
(see launcher/RELEASES.md for the full naming + arg contract)

Photon AppIds, JWT secret, and the picked Rec Room path stay
per-machine; the launcher never bundles them.

launcher/RELEASES.md

@@ -0,0 +1,96 @@
+# Release artifact contract
+
+The DorkNet Launcher (on `main`) reads
+[`/versions.json`](../versions.json) to find every supported per-version
+branch, then fetches release artifacts from each branch's GitHub
+Releases.
+
+Per-version branches must publish releases that follow this contract,
+otherwise the launcher reports "no release found" to users on host /
+join.
+
+## Tag naming
+
+A release's tag must start with the `release_tag_prefix` declared for
+the branch in `versions.json`. Recommended scheme:
+
+```
+v1-{month}-{YYYY.MM.DD}
+```
+
+Examples (matching the current `release_tag_prefix` values):
+
+| Branch | `release_tag_prefix` | Example full tag |
+|---|---|---|
+| `december-2020-12-18` | `v1-december` | `v1-december-2026.06.15` |
+| `march-2020-03-10` | `v1-march` | `v1-march-2026.06.15` |
+
+The launcher picks the most-recent release (by `published_at`) whose
+tag starts with the prefix, then looks for the asset names below.
+
+## Required assets
+
+Each release must attach these two files:
+
+### 1. `dorknet-server-{version_key}-win-x64.zip`
+
+A self-contained .NET 9 publish of `DorkNet.Server` for `win-x64`.
+The launcher unpacks this and spawns the executable directly.
+
+Build with:
+
+```pwsh
+cd DorkNet.Server
+dotnet publish -c Release -r win-x64 --self-contained -p:PublishSingleFile=true
+# Then zip the publish dir's contents (NOT the dir itself):
+cd bin/Release/net9.0/win-x64/publish
+Compress-Archive -Path * -DestinationPath ../../../../../dorknet-server-{version_key}-win-x64.zip
+```
+
+The zip's root must contain `DorkNet.Server.exe` (or any `.exe`; the
+launcher scans for it). Folder layout below that is preserved as-is.
+
+### 2. `dorknet-clientpatch-{version_key}.zip`
+
+The contents of the per-version branch's `tools/` directory limited
+to the patcher scripts the launcher invokes:
+
+- `install-plugin.ps1` (preferred — BepInEx route)
+- `install-legacy-client.ps1` (fallback — direct byte-patch route)
+- Any helper scripts these reference
+- The compiled `DorkNet.ClientPatch.dll` if `install-plugin.ps1`
+  expects a prebuilt DLL
+
+The launcher invokes the patcher script with these arguments:
+
+```
+powershell -NoProfile -ExecutionPolicy Bypass -File install-plugin.ps1 `
+  -RecRoomPath <user's path> `
+  -PhotonAppId <user's> `
+  -PhotonVoiceAppId <user's> `
+  -ServerHost <apex host or join-code host>
+```
+
+So the script must accept those four parameters. If your branch's
+patcher needs additional config, default to safe values.
+
+## Verifying a release before publishing
+
+```pwsh
+# Locally simulate the launcher's fetch.
+$tag = "v1-december-2026.06.15"
+gh release view $tag --repo DorkSquadRR/DorkNet
+gh release download $tag --repo DorkSquadRR/DorkNet `
+  --pattern "dorknet-server-december_2020_12_18-win-x64.zip" `
+  --pattern "dorknet-clientpatch-december_2020_12_18.zip"
+```
+
+Then unzip + boot the server locally to confirm it starts, and
+unzip + run the patcher against a clean Rec Room install to confirm
+patching works.
+
+## Future: GitHub Actions workflow
+
+Each per-version branch should land a `.github/workflows/release.yml`
+that builds + zips + publishes the two artifacts on tag push. Not yet
+implemented; releases are manual for now.