The brace that closed nothing took the car screens with it

CarStrings' placeholder pattern escaped its opening brace and left the
closing one bare. Desktop java.util.regex reads a lone "}" as a literal;
Android compiles through ICU, which refuses it. So the companion object
threw PatternSyntaxException the first time anything touched it, which is
VaultScreen's constructor, which is every car screen there is — the host
bound the service, the app died, and the head unit sat black with nothing
in the log but a clean bind.

i18n.dart, which this is the twin of, escapes both. Do the same.

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

Phone App/android/app/src/main/kotlin/com/drivervault/phoneapp/car/CarStrings.kt

@@ -40,7 +40,12 @@ class CarStrings private constructor(
 
     companion object {
         private const val BASE = "en"
-        private val PLACEHOLDER = Regex("""\{(\w+)}""")
+        // Both braces escaped, as in i18n.dart's twin of this pattern.
+        // Android compiles regexes through ICU rather than java.util.regex,
+        // and ICU refuses a closing brace that opens no quantifier — a lone
+        // "}" here throws PatternSyntaxException the first time CarStrings
+        // is touched, which on a head unit is a screen that never draws.
+        private val PLACEHOLDER = Regex("""\{(\w+)\}""")
 
         /** Loads the files for the account's language, falling back to English. */
         fun of(context: Context): CarStrings {