Remove SubscriptionError — no subscription feature in this app

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: dadachi

CLAUDE.md

@@ -56,7 +56,6 @@ All errors should use the `CodedError` interface. Error codes use the `NATA-XXXX
 | NATA-1xxx | App/general errors | Unexpected errors, catch-all |
 | NATA-2xxx | API/network errors | HTTP request failures, parsing errors |
 | NATA-3xxx | NFC/scan errors | NFC tag read/write/scan failures |
-| NATA-6xxx | Subscription errors | Purchase, restore, offering failures |
 
 - New error types must implement `CodedError`
 - Use `codedDescription` (not `message` or `localizedMessage`) in all user-facing error messages — this prepends `[NATA-XXXX]` for `CodedError` types

app/src/main/kotlin/com/nativeapptemplate/nativeapptemplatefree/common/errors/SubscriptionError.kt

@@ -55,20 +55,6 @@ class CodedErrorTest {
     assertEquals("[NATA-3001] NFC scan operation failed: tag lost", error.formattedDescription)
   }
 
-  @Test
-  fun subscriptionError_restoreFailed_hasCorrectCode() {
-    val error = SubscriptionError.RestoreFailed()
-    assertEquals("NATA-6001", error.errorCode)
-    assertEquals("[NATA-6001] Failed to restore purchases", error.formattedDescription)
-  }
-
-  @Test
-  fun subscriptionError_subscriptionRequired_hasCorrectCode() {
-    val error = SubscriptionError.SubscriptionRequired()
-    assertEquals("NATA-6002", error.errorCode)
-    assertEquals("[NATA-6002] User needs an active subscription", error.formattedDescription)
-  }
-
   @Test
   fun codedDescription_forCodedError_returnsFormattedDescription() {
     val error: Throwable = ApiException.ApiError(code = 500, apiMessage = "Server error")