add microphone capture and stable code signing for TCC persistence

Adds --capture-mic/--mic-output for a second, independently-captured audio
track (mic vs system, written to separate outputs to avoid interleaving
corruption). Embeds Info.plist at link time so the binary carries a stable
CFBundleIdentifier and the usage-description keys TCC requires, and adds
scripts/build-signed.sh + scripts/create-signing-identity.sh so a rebuilt
binary keeps the same signing identity instead of losing granted
permissions on every rebuild.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Package.swift

@@ -31,7 +31,19 @@ let package = Package(
     .executableTarget(
       name: "AudioTeeCLI",
       dependencies: ["AudioTeeCore"],
-      path: "Sources/AudioTeeCLI"
+      path: "Sources/AudioTeeCLI",
+      exclude: ["Info.plist"],
+      linkerSettings: [
+        // Embeds Info.plist directly into the Mach-O binary so it carries a
+        // stable CFBundleIdentifier and the usage-description keys TCC needs,
+        // without requiring a full .app bundle — see scripts/build-signed.sh.
+        .unsafeFlags([
+          "-Xlinker", "-sectcreate",
+          "-Xlinker", "__TEXT",
+          "-Xlinker", "__info_plist",
+          "-Xlinker", "Sources/AudioTeeCLI/Info.plist",
+        ])
+      ]
     ),
     
     // Tests for the library