refactor(liveobjects): delegate no-arg counter mutators to their Number overloads

The parameterless increment()/decrement() on both DefaultLiveCounterPathObject and
DefaultLiveCounterInstance duplicated the full body of their Number counterparts with
a hardcoded 1. Make them delegate to increment(1)/decrement(1) instead. All spec
checks live in the parameterized overload, and the default-of-1 spec points
(RTPO17a1/RTPO18a1, RTINS14a1/RTINS15a1) are preserved on the delegating methods.
Pure refactor, no behaviour change.

Author: sacOO7

liveobjects/src/main/kotlin/io/ably/lib/liveobjects/instance/types/DefaultLiveCounterInstance.kt

@@ -36,20 +36,16 @@ internal class DefaultLiveCounterInstance(
     return counter.value() // RTINS4b via RTLC5c; RTTS10b non-null
   }
 
-  override fun increment(): CompletableFuture<Void> {
-    channelObject.throwIfInvalidWriteApiConfiguration() // RTINS14b
-    return channelObject.asyncVoidApi { counter.increment(1) } // RTINS14a1 default, RTINS14c -> RTLC12
-  }
+  // RTINS14a1 - default amount of 1; delegates to increment(Number)
+  override fun increment(): CompletableFuture<Void> = increment(1)
 
   override fun increment(amount: Number): CompletableFuture<Void> {
     channelObject.throwIfInvalidWriteApiConfiguration() // RTINS14b
     return channelObject.asyncVoidApi { counter.increment(amount) } // RTINS14c -> RTLC12
   }
 
-  override fun decrement(): CompletableFuture<Void> {
-    channelObject.throwIfInvalidWriteApiConfiguration() // RTINS15b
-    return channelObject.asyncVoidApi { counter.decrement(1) } // RTINS15a1 default, RTINS15c -> RTLC13
-  }
+  // RTINS15a1 - default amount of 1; delegates to decrement(Number)
+  override fun decrement(): CompletableFuture<Void> = decrement(1)
 
   override fun decrement(amount: Number): CompletableFuture<Void> {
     channelObject.throwIfInvalidWriteApiConfiguration() // RTINS15b

liveobjects/src/main/kotlin/io/ably/lib/liveobjects/path/types/DefaultLiveCounterPathObject.kt

@@ -27,14 +27,8 @@ internal class DefaultLiveCounterPathObject(
     return counter.value() // RTPO7c via RTLC5c
   }
 
-  override fun increment(): CompletableFuture<Void> {
-    channelObject.throwIfInvalidWriteApiConfiguration() // RTPO17b / RTO26
-    val resolvedValue = resolveValueAtCurrentPath() ?: throw pathNotResolvedError(path) // RTPO17c / RTPO3c2
-    if (resolvedValue !is ResolvedValue.CounterRef) {
-      throw typeMismatchError("Cannot increment a non-LiveCounter object at path: \"$path\"") // RTPO17e
-    }
-    return channelObject.asyncVoidApi { resolvedValue.counter.increment(1) } // RTPO17a1 default, RTPO17d -> RTLC12
-  }
+  // RTPO17a1 - default amount of 1; delegates to increment(Number)
+  override fun increment(): CompletableFuture<Void> = increment(1)
 
   override fun increment(amount: Number): CompletableFuture<Void> {
     channelObject.throwIfInvalidWriteApiConfiguration() // RTPO17b / RTO26
@@ -45,14 +39,8 @@ internal class DefaultLiveCounterPathObject(
     return channelObject.asyncVoidApi { resolvedValue.counter.increment(amount) } // RTPO17d -> RTLC12
   }
 
-  override fun decrement(): CompletableFuture<Void> {
-    channelObject.throwIfInvalidWriteApiConfiguration() // RTPO18b / RTO26
-    val resolvedValue = resolveValueAtCurrentPath() ?: throw pathNotResolvedError(path) // RTPO18c / RTPO3c2
-    if (resolvedValue !is ResolvedValue.CounterRef) {
-      throw typeMismatchError("Cannot decrement a non-LiveCounter object at path: \"$path\"") // RTPO18e
-    }
-    return channelObject.asyncVoidApi { resolvedValue.counter.decrement(1) } // RTPO18a1 default, RTPO18d -> RTLC13
-  }
+  // RTPO18a1 - default amount of 1; delegates to decrement(Number)
+  override fun decrement(): CompletableFuture<Void> = decrement(1)
 
   override fun decrement(amount: Number): CompletableFuture<Void> {
     channelObject.throwIfInvalidWriteApiConfiguration() // RTPO18b / RTO26