ci: add App Size check job

.github/size-check/.gitignore

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+# Generated by xcodegen at run time.
+SizeCheck.xcodeproj/
+EmptyApp/Info.plist
+LiveKitApp/Info.plist

.github/size-check/EmptyApp/App.swift

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+/*
+ * Copyright 2026 LiveKit
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import SwiftUI
+
+@main
+struct EmptyApp: App {
+    var body: some Scene {
+        WindowGroup {
+            Text("Hello, World!")
+        }
+    }
+}

.github/size-check/LiveKitApp/App.swift

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+/*
+ * Copyright 2026 LiveKit
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import LiveKit
+import SwiftUI
+
+// Exercises a representative slice of the public API (connect + publish camera/mic
+// + a video view) so the linker keeps the main code paths.
+@MainActor
+final class CallModel: ObservableObject, RoomDelegate {
+    let room = Room()
+
+    init() {
+        room.add(delegate: self)
+    }
+
+    func connect() async {
+        do {
+            try await room.connect(url: "wss://example.livekit.cloud", token: "dev-token")
+            try await room.localParticipant.setCamera(enabled: true)
+            try await room.localParticipant.setMicrophone(enabled: true)
+        } catch {
+            print("Failed to connect: \(error)")
+        }
+    }
+
+    nonisolated func room(
+        _: Room,
+        participant _: LocalParticipant,
+        didPublishTrack publication: LocalTrackPublication,
+    ) {
+        guard publication.track is VideoTrack else { return }
+        print("Published a video track")
+    }
+}
+
+@main
+struct LiveKitApp: App {
+    @StateObject private var model = CallModel()
+
+    var body: some Scene {
+        WindowGroup {
+            VStack {
+                Text("LiveKit Hello World")
+                if let track = model.room.localParticipant.localVideoTracks.first?.track as? VideoTrack {
+                    SwiftUIVideoView(track)
+                }
+            }
+            .task { await model.connect() }
+        }
+    }
+}

.github/size-check/project.yml

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+name: SizeCheck
+options:
+  bundleIdPrefix: io.livekit.sizecheck
+  deploymentTarget:
+    iOS: "26.0"
+  createIntermediateGroups: true
+
+# Local SDK under test = the repo root (this PR's checkout), two levels up.
+packages:
+  LiveKit:
+    path: ../..
+
+settings:
+  base:
+    CODE_SIGNING_ALLOWED: "NO"
+    CODE_SIGNING_REQUIRED: "NO"
+    CODE_SIGN_IDENTITY: ""
+    ENABLE_BITCODE: "NO"
+    SWIFT_OPTIMIZATION_LEVEL: "-O"
+    DEAD_CODE_STRIPPING: "YES"
+
+targets:
+  EmptyApp:
+    type: application
+    platform: iOS
+    sources: [EmptyApp]
+    # xcodegen generates this Info.plist during `generate` (gitignored, not committed).
+    info:
+      path: EmptyApp/Info.plist
+      properties:
+        UILaunchScreen: {}
+    settings:
+      base:
+        PRODUCT_BUNDLE_IDENTIFIER: io.livekit.sizecheck.empty
+
+  LiveKitApp:
+    type: application
+    platform: iOS
+    sources: [LiveKitApp]
+    dependencies:
+      - package: LiveKit
+        product: LiveKit
+    info:
+      path: LiveKitApp/Info.plist
+      properties:
+        UILaunchScreen: {}
+    settings:
+      base:
+        PRODUCT_BUNDLE_IDENTIFIER: io.livekit.sizecheck.livekit
+        # Per-target link map (unique path) for per-library executable attribution.
+        LD_GENERATE_MAP_FILE: "YES"
+        LD_MAP_FILE_PATH: "$(TARGET_TEMP_DIR)/LiveKitApp-LinkMap.txt"
+
+schemes:
+  EmptyApp:
+    build:
+      targets: { EmptyApp: all }
+    archive:
+      config: Release
+  LiveKitApp:
+    build:
+      targets: { LiveKitApp: all }
+    archive:
+      config: Release