Live view over WebRTC (openpanel L1, server and browser)

A device reporting a `live` port streams its camera to the browser's own
RTCPeerConnection. The flows socket carries the signalling as text, so it
crosses the portal: `live` messages on a person's socket, `signal` on a
device's (start, sdp, candidate, bye, busy). The server routes by session,
holds a device to two viewers, ends a session when either socket closes or
no answer comes within 10 s, and gives each socket an outbox of its own
that ends a session rather than drop a message. TURN credentials are
minted per session in coturn's REST scheme (STUN_URLS, TURN_URLS,
TURN_SECRET), the viewer's with the device's offer; GET /devices/{id}/ice
hands them out too. The tunnel keeps a stream's early frames instead of
dropping them past eight and forgets them when the stream or link goes.

A media tile on a device's camera, and the Devices tab's preview, play
live when tapped, pause frames meanwhile, and fall back to frames with a
short note on busy, failure or no picture within 10 s. coturn is an
optional compose service behind the `turn` profile.

frontend/src/client/schemas.gen.ts

@@ -2006,6 +2006,63 @@ export const HistoryPointSchema = {
     description: 'One numeric value a message carried, and when.'
 } as const;
 
+export const IceServerSchema = {
+    properties: {
+        urls: {
+            items: {
+                type: 'string'
+            },
+            type: 'array',
+            title: 'Urls'
+        },
+        username: {
+            anyOf: [
+                {
+                    type: 'string'
+                },
+                {
+                    type: 'null'
+                }
+            ],
+            title: 'Username'
+        },
+        credential: {
+            anyOf: [
+                {
+                    type: 'string'
+                },
+                {
+                    type: 'null'
+                }
+            ],
+            title: 'Credential'
+        }
+    },
+    type: 'object',
+    required: ['urls'],
+    title: 'IceServer',
+    description: 'One STUN or TURN server, as `RTCPeerConnection` takes it.'
+} as const;
+
+export const IceServersSchema = {
+    properties: {
+        ice_servers: {
+            items: {
+                '$ref': '#/components/schemas/IceServer'
+            },
+            type: 'array',
+            title: 'Ice Servers'
+        },
+        ttl: {
+            type: 'integer',
+            title: 'Ttl',
+            default: 0
+        }
+    },
+    type: 'object',
+    title: 'IceServers'
+} as const;
+
 export const ImportArtifactSchema = {
     properties: {
         name: {

frontend/src/client/types.gen.ts

@@ -686,6 +686,20 @@ export type HTTPValidationError = {
     detail?: Array<ValidationError>;
 };
 
+/**
+ * One STUN or TURN server, as `RTCPeerConnection` takes it.
+ */
+export type IceServer = {
+    urls: Array<(string)>;
+    username?: (string | null);
+    credential?: (string | null);
+};
+
+export type IceServers = {
+    ice_servers?: Array<IceServer>;
+    ttl?: number;
+};
+
 export type ImportArtifact = {
     name: string;
     filename?: (string | null);
@@ -1879,6 +1893,12 @@ export type DevicesDeleteDeviceData = {
 
 export type DevicesDeleteDeviceResponse = (Message);
 
+export type DevicesReadIceData = {
+    deviceId: string;
+};
+
+export type DevicesReadIceResponse = (IceServers);
+
 export type DevicesPutReportData = {
     deviceId: string;
 };