feat(server): impl storage runtime (#15181)

#### PR Dependency Tree


* **PR #15181** 👈

This tree was auto-generated by
[Charcoal](https://github.com/danerwilliams/charcoal)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Added an additional storage backend option: asset-pack based storage
(provider for avatar, blob, and copilot).
* Introduced a dedicated storage runtime with provider capability
reporting and expanded object operations (put/head/get/list/delete),
including presigned and multipart flows where supported.
* Cloudflare R2 `jurisdiction` now uses an explicit default when
omitted.
* **Bug Fixes**
  * Broadened avatar access to allow both fs and asset-pack providers.
* Improved workspace blob upload completion validation and handling when
stored objects are missing or mismatched.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/native/src/runtime/migrations.rs

@@ -0,0 +1,20 @@
+use sqlx::PgPool;
+
+use super::{RuntimeError, RuntimeResult};
+
+pub(crate) const RUNTIME_MIGRATIONS: &str = include_str!("sql/runtime_migrations.sql");
+
+pub(crate) async fn migrate_runtime_tables(pool: &PgPool) -> RuntimeResult<()> {
+  for statement in RUNTIME_MIGRATIONS
+    .split(';')
+    .map(str::trim)
+    .filter(|statement| !statement.is_empty())
+  {
+    sqlx::query(statement)
+      .execute(pool)
+      .await
+      .map_err(|err| RuntimeError::database("Runtime migration failed", err))?;
+  }
+
+  Ok(())
+}