refactor(proto): use Wire native emitAppliedOptions, delete custom SchemaHandler

The upstream proto (meshtastic/protobufs#905) has been simplified to use
a scalar bool extension instead of a message wrapper:
  [(meshtastic.diy_only) = true]
Wire 6's emitAppliedOptions now natively generates @DiyOnlyOption(true)
annotations on fields, eliminating the need for our custom
FieldMetadataSchemaHandler.
Changes:
- Delete FieldMetadataSchemaHandler.kt (~200 LOC)
- Remove wire-schema dependency from build-logic
- Remove custom {} handler block from core:proto build
- Add emitAppliedOptions = true to Wire kotlin {} config
- Update FieldMetadataDemo to demonstrate the native annotation
- Bump protobufs submodule to metadata-experiment branch

Author: jamesarich

build-logic/convention/build.gradle.kts

@@ -56,7 +56,6 @@ dependencies {
     compileOnly(libs.androidx.room.gradlePlugin)
     compileOnly(libs.spotless.gradlePlugin)
     compileOnly(libs.test.retry.gradlePlugin)
-    implementation(libs.wire.schema)
 
     detektPlugins(libs.detekt.formatting)
 }

build-logic/convention/src/main/kotlin/org/meshtastic/buildlogic/proto/FieldMetadataSchemaHandler.kt

@@ -30,7 +30,6 @@ kotlin {
     sourceSets {
         commonMain {
             dependencies { api(libs.wire.runtime) }
-            kotlin.srcDir(layout.buildDirectory.dir("generated/source/wire-metadata"))
         }
     }
 }
@@ -50,15 +49,10 @@ wire {
         // Codebase is already written to use the nullable properties (e.g. packet.decoded vs
         // packet.payload_variant.decoded).
         boxOneOfsMinSize = 5000
-    }
-    // Emit a static ConfigFieldMetadataRegistry from (meshtastic.config_field) annotations.
-    // Fully automatic — annotating new proto fields requires no changes here or in the handler.
-    // Only modify the handler if ConfigFieldMetadata gains new sub-fields.
-    custom {
-        schemaHandlerFactoryClass =
-            "org.meshtastic.buildlogic.proto.FieldMetadataSchemaHandlerFactory"
-        out = layout.buildDirectory.dir("generated/source/wire-metadata").get().asFile.path
-        exclusive = false
+
+        // Emit Kotlin annotations from scalar proto field options (e.g. diy_only).
+        // Wire natively generates @DiyOnly annotations on fields that carry the option.
+        emitAppliedOptions = true
     }
     root("meshtastic.*")
     prune("meshtastic.MeshPacket#delayed")

core/proto/build.gradle.kts

@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2025-2026 Meshtastic LLC
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+package org.meshtastic.core.proto
+
+import org.meshtastic.proto.DiyOnlyOption
+
+/**
+ * DEMO: Wire 6 natively generates `@DiyOnlyOption(true)` on proto fields that carry
+ * `[(meshtastic.diy_only) = true]` — zero custom build code needed.
+ *
+ * The annotation has `RUNTIME` retention and targets `PROPERTY` + `FIELD`, so
+ * it can be queried via reflection on JVM/Android or used as a compile-time marker.
+ *
+ * Generated code in `Config.PositionConfig`:
+ * ```kotlin
+ * @DiyOnlyOption(true)
+ * @field:WireField(tag = 8, ...)
+ * public val rx_gpio: Int = 0,
+ * ```
+ *
+ * See: https://github.com/meshtastic/protobufs/pull/905
+ */
+object FieldMetadataDemo {
+
+    /**
+     * The [DiyOnlyOption] annotation is available at compile time for reference.
+     * On JVM/Android, you can reflect over it at runtime:
+     *
+     * ```kotlin
+     * // JVM/Android only (kotlin-reflect):
+     * val isDiy = Config.PositionConfig::rx_gpio
+     *     .findAnnotation<DiyOnlyOption>()?.value ?: false
+     * ```
+     *
+     * For KMP-safe access without reflection, use a constants map:
+     */
+    val diyOnlyFields: Set<String> = setOf("rx_gpio", "tx_gpio")
+
+    /**
+     * UI gating — hide settings that are diy_only when device isn't DIY:
+     *
+     * ```kotlin
+     * if ("rx_gpio" !in FieldMetadataDemo.diyOnlyFields || deviceIsDiy) {
+     *     DropDownPreference(title = stringResource(Res.string.gps_receive_gpio), ...)
+     * }
+     * ```
+     */
+    fun uiGatingExample(deviceIsDiy: Boolean) {
+        val allFields = listOf("fixed_position", "gps_enabled", "rx_gpio", "tx_gpio")
+        for (field in allFields) {
+            val isDiyOnly = field in diyOnlyFields
+            if (!isDiyOnly || deviceIsDiy) {
+                println("Showing $field setting")
+            }
+        }
+    }
+}