docs: add the streaming webstation migration guide

docs/Navigation.md

@@ -55,6 +55,7 @@ search:
         - [MS-DOS](using/in-browser-play/ms-dos.md)
         - [Ruffle](using/in-browser-play/ruffle.md)
     - [Emulator Streaming](using/emulator-streaming.md)
+        - [Migrating to webstation](using/emulator-streaming-migration.md)
     - [Saves & States](using/saves-and-states.md)
     - [RetroAchievements](using/retroachievements.md)
     - [ROM Patcher](using/rom-patcher.md)

docs/using/emulator-streaming-migration.md

@@ -0,0 +1,80 @@
+---
+title: Migrating Streaming to webstation
+description: Move from one broker container per emulator to a single webstation container
+---
+
+# Migrating Streaming to webstation
+
+Emulator streaming used to mean one container per emulator, each running its own broker mod (`pcsx2-romm-integration`, `dolphin-romm-integration`, `xemu-romm-integration`, `rpcs3-romm-integration`). Going forward, streaming goes through a single [docker-webstation](https://github.com/linuxserver/docker-webstation) container running [romm-broker](https://github.com/romm-streaming/romm-broker), which can serve every platform RomM streams from one place instead of one container per emulator.
+
+<!-- prettier-ignore -->
+!!! warning "The per-emulator broker mods are deprecated"
+    A `config.yml` container without `protocol: webstation` still works today, logs a startup warning telling you to migrate, and will stop being supported in a future release.
+
+## Why
+
+- One container to run and update instead of N forks of the same broker pattern, each drifting slightly.
+- One save-state and memory-card contract instead of five slightly different ones.
+- A platform pool (`platforms:` on one container) claims whichever instance is free, instead of every platform being pinned to its own single container.
+
+## Migrating your `config.yml`
+
+Before, one container per platform:
+
+```yaml
+streaming:
+    containers:
+        - platform: ps2
+          host: https://192.168.1.51:3001
+          broker_host: http://192.168.1.51:8000
+          label: PCSX2
+          memory_card_sync: true
+        - platform: ngc
+          host: https://192.168.1.52:3001
+          broker_host: http://192.168.1.52:8000
+          label: Dolphin
+```
+
+After, one webstation container serving both:
+
+```yaml
+streaming:
+    containers:
+        - host: https://192.168.1.56:3010
+          protocol: webstation
+          subfolder: /streaming
+          library_path: /romm
+          label: Emulation station
+          platforms:
+              ps2:
+                  emulator: pcsx2
+                  label: PCSX2
+                  memory_card_sync: true
+              ngc:
+                  emulator: dolphin
+                  label: Dolphin
+```
+
+The full field reference lives in [Configuration File → `streaming`](../reference/configuration-file.md#streaming).
+
+## Migrating your containers
+
+1. Stand up [docker-webstation](https://github.com/linuxserver/docker-webstation) with [romm-broker](https://github.com/romm-streaming/romm-broker) mounted at your ROM library path (use the same path your old per-emulator containers used, so save/state history keyed to it doesn't reset).
+2. Point `library_path` in `config.yml` at that same mount.
+3. Move each platform you were streaming into the new container's `platforms:` map (see the before/after above).
+4. Confirm streaming works for each platform, then remove the old per-emulator containers.
+5. Restart RomM. The startup warning about legacy containers disappears once no `config.yml` container is missing `protocol: webstation`.
+
+## Per-emulator notes
+
+Save data, memory cards, and BIOS/firmware requirements don't change, only which container runs the emulator. See the "Migrating to webstation" section in:
+
+- [pcsx2-romm-integration](https://github.com/LoneAngelFayt/pcsx2-romm-integration)
+- [dolphin-romm-integration](https://github.com/LoneAngelFayt/dolphin-romm-integration)
+- [xemu-romm-integration](https://github.com/LoneAngelFayt/xemu-romm-integration)
+- [rpcs3-romm-integration](https://github.com/LoneAngelFayt/rpcs3-romm-integration)
+
+## Related
+
+- [Emulator Streaming](emulator-streaming.md): the setup guide for streaming as a whole
+- [Configuration File → `streaming`](../reference/configuration-file.md#streaming): every key the `streaming` block accepts

docs/using/emulator-streaming.md

@@ -9,6 +9,10 @@ Emulator streaming launches a game into a **native** emulator running in a separ
 
 Each emulator runs in its own [linuxserver](https://docs.linuxserver.io) container with a [Selkies](https://github.com/selkies-project/selkies) WebRTC stream and a small HTTP broker sidecar that RomM talks to. Nothing appears in the UI until you configure at least one container.
 
+<!-- prettier-ignore -->
+!!! info "Already running per-emulator containers?"
+    Streaming is moving to a single webstation container that serves every platform. See [Migrating to webstation](emulator-streaming-migration.md).
+
 <!-- prettier-ignore -->
 !!! warning "Work in progress"
     This is the first release of the streaming framework and ships with four emulators. More integrations (rpcs3 for PS3, and others) are planned as separate follow-ups.