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/common/native/src/hashcash.rs

@@ -40,7 +40,7 @@ impl Stamp {
       // check challenge
       let mut hasher = Sha3_256::new();
       hasher.update(self.format().as_bytes());
-      let result = format!("{:x}", hasher.finalize());
+      let result = hex::encode(hasher.finalize());
       result[..hex_digits] == String::from_utf8(vec![b'0'; hex_digits]).unwrap()
     } else {
       false
@@ -77,7 +77,7 @@ impl Stamp {
         let zeros = String::from_utf8(vec![b'0'; hex_digits]).unwrap();
         loop {
           hasher.update(format!("{challenge}:{counter:x}").as_bytes());
-          let result = format!("{:x}", hasher.finalize_reset());
+          let result = hex::encode(hasher.finalize_reset());
           if result[..hex_digits] == zeros {
             break format!("{counter:x}");
           };