iOS: centralize canvas commands and capabilities

apps/ios/Sources/Bridge/BridgeConnectionController.swift

@@ -155,17 +155,17 @@ final class BridgeConnectionController {
     }
 
     private func currentCaps() -> [String] {
-        var caps = ["canvas"]
+        var caps = [ClawdisCapability.canvas.rawValue]
 
         // Default-on: if the key doesn't exist yet, treat it as enabled.
         let cameraEnabled =
             UserDefaults.standard.object(forKey: "camera.enabled") == nil
                 ? true
                 : UserDefaults.standard.bool(forKey: "camera.enabled")
-        if cameraEnabled { caps.append("camera") }
+        if cameraEnabled { caps.append(ClawdisCapability.camera.rawValue) }
 
         let voiceWakeEnabled = UserDefaults.standard.bool(forKey: VoiceWakePreferences.enabledKey)
-        if voiceWakeEnabled { caps.append("voiceWake") }
+        if voiceWakeEnabled { caps.append(ClawdisCapability.voiceWake.rawValue) }
 
         return caps
     }

apps/ios/Sources/Model/NodeAppModel.swift

@@ -266,12 +266,7 @@ final class NodeAppModel {
 
     private func handleInvoke(_ req: BridgeInvokeRequest) async -> BridgeInvokeResponse {
         // Alias for "canvas" capability: accept canvas.* commands and map them to screen.*.
-        let command =
-            if req.command.hasPrefix("canvas.") {
-                "screen." + req.command.dropFirst("canvas.".count)
-            } else {
-                req.command
-            }
+        let command = ClawdisInvokeCommandAliases.canonicalizeCanvasToScreen(req.command)
 
         if command.hasPrefix("screen.") || command.hasPrefix("camera."), self.isBackgrounded {
             return BridgeInvokeResponse(