Harden PTT audio and the 1.7.1 release (#1423)

Centralize PTT and voice audio-session ownership, harden courier/bridge/outbox delivery and recovery, correct location and delivery-state races, add privacy/release metadata, and ship reproducible universal Arti slices with Release CI coverage.

Validated by the full iOS suite, repeated audio/fragment/performance regressions, BitFoundation tests, strict lint and dead-code analysis, universal iOS Release builds, and iOS/macOS archives.

localPackages/Arti/Frameworks/arti.xcframework/Info.plist

@@ -26,12 +26,13 @@
 			<key>HeadersPath</key>
 			<string>Headers</string>
 			<key>LibraryIdentifier</key>
-			<string>ios-arm64-simulator</string>
+			<string>ios-arm64_x86_64-simulator</string>
 			<key>LibraryPath</key>
 			<string>libarti_bitchat.a</string>
 			<key>SupportedArchitectures</key>
 			<array>
 				<string>arm64</string>
+				<string>x86_64</string>
 			</array>
 			<key>SupportedPlatform</key>
 			<string>ios</string>
@@ -44,12 +45,13 @@
 			<key>HeadersPath</key>
 			<string>Headers</string>
 			<key>LibraryIdentifier</key>
-			<string>macos-arm64</string>
+			<string>macos-arm64_x86_64</string>
 			<key>LibraryPath</key>
 			<string>libarti_bitchat.a</string>
 			<key>SupportedArchitectures</key>
 			<array>
 				<string>arm64</string>
+				<string>x86_64</string>
 			</array>
 			<key>SupportedPlatform</key>
 			<string>macos</string>