build: support persistent signing identity for Accessibility

Makefile

@@ -2,6 +2,7 @@
 
 APP := .build/Conjure.app
 INSTALL_DIR ?= /Applications
+CODE_SIGN_IDENTITY ?= -
 
 build:
 	swift build -c release
@@ -11,7 +12,7 @@ build:
 	cp -R .build/release/Conjure_ConjureKit.bundle $(APP)/Contents/Resources/
 	swift Scripts/icon.swift .build/Conjure.iconset
 	iconutil -c icns .build/Conjure.iconset -o $(APP)/Contents/Resources/Conjure.icns
-	codesign --force --sign - $(APP)
+	codesign --force --sign "$(CODE_SIGN_IDENTITY)" $(APP)
 
 run: build
 	swift Scripts/run.swift "$(APP)"