Add multi-player and remote bridge support

docs/README.md

@@ -0,0 +1,13 @@
+# Documentation
+
+This folder contains the technical reference material for Pulse Signage.
+
+## What’s Here
+
+- [API reference](api.md) - the player HTTP surface and onboarding endpoints.
+- [Database schema](schema.md) - the tables and data model used by the app.
+- [WebSocket reference](websocket.md) - the live player and snapshot channels.
+
+## How To Read It
+
+If you want the big picture first, start with the main [project README](../README.md). It gives a plain overview of what Pulse Signage does, while the pages in this folder explain how the pieces work.

docs/schema.md

@@ -112,7 +112,7 @@ Primary keys are `id` unless noted otherwise. Timestamps are stored as `created_
 ## Devices
 
 - `d_players` - player registry and connection metadata.
-- `d_screens` - screen records and playlist/player assignment.
+- `d_screens` - screen records and playlist assignment.
 - `d_onboarding_devices` - device-to-screen bindings and onboarded client names.
 
 ## Announcements
@@ -122,18 +122,18 @@ Primary keys are `id` unless noted otherwise. Timestamps are stored as `created_
 
 ### `d_players`
 
-- `device_id`, `public_base_url`, `internal_base_url`, `last_seen_at`, `created_at`, `modified_at`
-- `device_id` is the primary key.
+- `id`, `identifier`, `public_base_url`, `internal_base_url`, `last_seen_at`, `created_at`, `modified_at`
+- `id` is the primary key.
+- `identifier` is unique and is the stable player identity used by the app.
         
 ### `d_screens`
 
-- `id`, `name`, `slug`, `playlist_id`, `player_id`, `created_at`, `created_by`, `modified_at`, `modified_by`
+- `id`, `name`, `slug`, `playlist_id`, `created_at`, `created_by`, `modified_at`, `modified_by`
 - `slug` is unique.
 - Foreign keys:
         - `playlist_id` -> `c_playlists.id` with `ON DELETE SET NULL`
-        - `player_id` -> `d_players.id` with `ON DELETE RESTRICT`
 
-- `player_id` is required and defaults to `'1'` for the current singleton-player model.
+- Screens are no longer tied to a player foreign key directly; player registration and live connection metadata are tracked separately in `d_players`.
 
 ### `d_onboarding_devices`
 
@@ -275,7 +275,6 @@ erDiagram
         C_SLIDES ||--o{ C_PLAYLIST_SLIDES : included_in
         C_PLAYLIST_SLIDES ||--o{ C_PLAYLIST_SLIDE_SCHEDULE_RULES : has_rules
 
-        D_PLAYERS ||--o{ D_SCREENS : assigned_to
         C_PLAYLISTS ||--o{ D_SCREENS : uses
         D_SCREENS ||--o{ D_ONBOARDING_DEVICES : binds
         D_ANNOUNCEMENTS ||--o{ D_ANNOUNCEMENT_SCREENS : targets