feat: improve mobile native impl (#14481)

fix #13529 

#### PR Dependency Tree


* **PR #14481** 👈

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**
* Mobile blob caching with file-backed storage for faster loads and
reduced network usage
* Blob decoding with lazy refresh on token-read failures for improved
reliability
  * Full-text search/indexing exposed to mobile apps
* Document sync APIs and peer clock management for robust cross-device
sync

* **Tests**
* Added unit tests covering payload decoding, cache safety, and
concurrency

* **Dependencies**
* Added an LRU cache dependency and a new mobile-shared package for
shared mobile logic
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Cargo.toml

@@ -46,6 +46,7 @@ resolver = "3"
   libc = "0.2"
   log = "0.4"
   loom = { version = "0.7", features = ["checkpoint"] }
+  lru = "0.16"
   memory-indexer = "0.3.0"
   mimalloc = "0.1"
   mp4parse = "0.17"