refactor(quartz): NIP-78 events use the build-template pattern

Convert both kind 30078 and the new kind 78 from the legacy
`suspend create(... signer)` shape to the now-standard
`build(...) -> EventTemplate` shape used across recent quartz events
(NIP-34, NIP-66, etc):

- Use `eventTemplate<T>(KIND, content, createdAt) { ... }` and lean
  on the shared `alt()` and `dTag()` TagArrayBuilder extensions
  instead of hand-rolling the `d`/`alt` injection.
- Callers now do `signer.sign(AppSpecificDataEvent.build(...))`.

For kind 78 the `d` tag is optional (it's a grouping key, not an
addressing key), so we keep it nullable and assemble it via
`DTag.assemble` — the typed `dTag()` extension is constrained to
addressable events, which is correct.

Update the lone caller (`AppSpecificState.saveNewAppSpecificData`).

amethyst/src/main/java/com/vitorpamplona/amethyst/model/nip78AppSpecific/AppSpecificState.kt

@@ -54,11 +54,11 @@ class AppSpecificState(
 
     suspend fun saveNewAppSpecificData(): AppSpecificDataEvent {
         val toInternal = settings.syncedSettings.toInternal()
-        return AppSpecificDataEvent.create(
-            dTag = APP_SPECIFIC_DATA_D_TAG,
-            description = signer.nip44Encrypt(JsonMapper.toJson(toInternal), signer.pubKey),
-            otherTags = emptyArray(),
-            signer = signer,
+        return signer.sign(
+            AppSpecificDataEvent.build(
+                dTag = APP_SPECIFIC_DATA_D_TAG,
+                description = signer.nip44Encrypt(JsonMapper.toJson(toInternal), signer.pubKey),
+            ),
         )
     }
 

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip78AppData/AppDataEvent.kt

@@ -23,9 +23,11 @@ package com.vitorpamplona.quartz.nip78AppData
 import androidx.compose.runtime.Immutable
 import com.vitorpamplona.quartz.nip01Core.core.Event
 import com.vitorpamplona.quartz.nip01Core.core.HexKey
-import com.vitorpamplona.quartz.nip01Core.signers.NostrSigner
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
+import com.vitorpamplona.quartz.nip01Core.tags.dTag.DTag
 import com.vitorpamplona.quartz.nip01Core.tags.dTag.dTag
-import com.vitorpamplona.quartz.nip31Alts.AltTag
+import com.vitorpamplona.quartz.nip31Alts.alt
 import com.vitorpamplona.quartz.utils.TimeUtils
 
 /**
@@ -52,30 +54,15 @@ class AppDataEvent(
         const val KIND = 78
         const val ALT = "Arbitrary app data"
 
-        suspend fun create(
+        fun build(
             content: String,
             dTag: String? = null,
-            otherTags: Array<Array<String>> = emptyArray(),
-            signer: NostrSigner,
             createdAt: Long = TimeUtils.now(),
-        ): AppDataEvent {
-            val withD =
-                if (dTag == null) {
-                    otherTags
-                } else if (otherTags.any { it.size > 1 && it[0] == "d" && it[1] == dTag }) {
-                    otherTags
-                } else {
-                    otherTags.filter { it.isEmpty() || it[0] != "d" }.toTypedArray() + arrayOf(arrayOf("d", dTag))
-                }
-
-            val newTags =
-                if (withD.none { it.isNotEmpty() && it[0] == "alt" }) {
-                    withD + arrayOf(AltTag.assemble(ALT))
-                } else {
-                    withD
-                }
-
-            return signer.sign(createdAt, KIND, newTags, content)
+            initializer: TagArrayBuilder<AppDataEvent>.() -> Unit = {},
+        ) = eventTemplate<AppDataEvent>(KIND, content, createdAt) {
+            alt(ALT)
+            dTag?.let { addUnique(DTag.assemble(it)) }
+            initializer()
         }
     }
 }

quartz/src/commonMain/kotlin/com/vitorpamplona/quartz/nip78AppData/AppSpecificDataEvent.kt

@@ -23,9 +23,11 @@ package com.vitorpamplona.quartz.nip78AppData
 import com.vitorpamplona.quartz.nip01Core.core.Address
 import com.vitorpamplona.quartz.nip01Core.core.BaseAddressableEvent
 import com.vitorpamplona.quartz.nip01Core.core.HexKey
-import com.vitorpamplona.quartz.nip01Core.signers.NostrSigner
+import com.vitorpamplona.quartz.nip01Core.core.TagArrayBuilder
+import com.vitorpamplona.quartz.nip01Core.signers.eventTemplate
 import com.vitorpamplona.quartz.nip01Core.tags.aTag.ATag
-import com.vitorpamplona.quartz.nip31Alts.AltTag
+import com.vitorpamplona.quartz.nip01Core.tags.dTag.dTag
+import com.vitorpamplona.quartz.nip31Alts.alt
 import com.vitorpamplona.quartz.utils.TimeUtils
 
 class AppSpecificDataEvent(
@@ -52,28 +54,15 @@ class AppSpecificDataEvent(
             dTag: String,
         ): ATag = ATag(KIND, pubkey, dTag, null)
 
-        suspend fun create(
+        fun build(
             dTag: String,
             description: String,
-            otherTags: Array<Array<String>>,
-            signer: NostrSigner,
             createdAt: Long = TimeUtils.now(),
-        ): AppSpecificDataEvent {
-            val withD =
-                if (otherTags.any { it.size > 1 && it[0] == "d" && it[1] == dTag }) {
-                    otherTags
-                } else {
-                    otherTags.filter { it.size > 0 && it[0] != "d" }.toTypedArray() + arrayOf("d", dTag)
-                }
-
-            val newTags =
-                if (withD.none { it.size > 0 && it[0] == "alt" }) {
-                    withD + AltTag.assemble(ALT)
-                } else {
-                    withD
-                }
-
-            return signer.sign(createdAt, KIND, newTags, description)
+            initializer: TagArrayBuilder<AppSpecificDataEvent>.() -> Unit = {},
+        ) = eventTemplate<AppSpecificDataEvent>(KIND, description, createdAt) {
+            alt(ALT)
+            dTag(dTag)
+            initializer()
         }
     }
 }