feat(memory): migrate EmbeddingProvider to KMP-compatible TextEmbeddingExecutor, add :memory-md-vector, and hybrid backend support

- Replaced `EmbeddingProvider` with cross-platform `TextEmbeddingExecutor` for native target compatibility.
- Introduced `:memory-md-vector` module combining vector-cache and `.md` file-based memory systems (`hybrid` backend).
- Updated `SiglipEmbeddingProvider` to use KMP `TextEmbeddingExtractor` and streamlined compatibility via `asExecutor`.
- Added hybrid memory backend to `standalone`, supporting `.md` reconciliation with vector-cache for semantic

outbox-inmemory/build.gradle.kts

@@ -0,0 +1,29 @@
+plugins {
+    alias(libs.plugins.kotlin.multiplatform)
+}
+
+// KMP-реализация [MutableOutboxStore] на `ArrayDeque` + `Mutex` — для тестов,
+// dev-режима и embedded-сценариев (Android core, CLI). TTL и size-cap eviction
+// вызываются на каждом `append`, в одном проходе с amortized O(1) для стабильного
+// размера буфера.
+//
+// Зависимости: только `:outbox-api` (api → `:proto` транзитивно).
+// Никакого I/O — pure in-memory.
+
+kotlin {
+    jvmToolchain(21)
+
+    jvm()
+    linuxX64()
+    mingwX64()
+
+    sourceSets {
+        commonMain.dependencies {
+            api(project(":outbox-api"))
+        }
+        commonTest.dependencies {
+            implementation(kotlin("test"))
+            implementation(libs.kotlinx.coroutines.test)
+        }
+    }
+}