fix(spoof): require = in global key-assignment check

isGlobalKeyAssignment treated any bare line whose first token
matched system/boot/vendor/all as a global assignment and
stripped it. A user line of literally "all" or "system" written
without a value (malformed config but reachable) thus got eaten
on the next atomicWrite. Require '=' in the trimmed line before
treating it as a key=value assignment.

app/src/main/java/org/matrix/TEESimulator/config/PatchLevelManager.kt

@@ -170,8 +170,8 @@ object PatchLevelManager {
     }
 
     private fun isGlobalKeyAssignment(trimmed: String): Boolean {
-        if (trimmed.isEmpty() || trimmed.startsWith("#")) return false
-        val key = trimmed.substringBefore("=").trim().lowercase()
+        if (trimmed.isEmpty() || trimmed.startsWith("#") || '=' !in trimmed) return false
+        val key = trimmed.substringBefore('=').trim().lowercase()
         return key in GLOBAL_KEYS
     }