reject with structured errors from the wasm bindings

crates/stitch-wasm/CHANGELOG.md

@@ -5,6 +5,24 @@ All notable changes to the `stitch-wasm` crate are documented here.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.5.0] - 2026-08-29
+
+### Changed
+
+- **Breaking:** a failed `Store` method now rejects with a structured JS `Error`
+  instead of a plain string. The `Error` carries `message` (the previous text)
+  and a stable `kind` discriminant — one of `conflict`, `ownership`, `notFound`,
+  `timeout`, `connectionClosed`, `sessionInvalid`, `mqtt`, `corruption` (a
+  corrupt local store — recover via `recoverPersistence`), `constraint` (a
+  permanent local schema/unique/foreign-key violation), `mqdb`, `config`,
+  `serde`, `io`, `notInitialized`, `alreadyInitialized`, `scopeNotActive`,
+  `unknownEntity`, `invalidInput` (a malformed argument), or `internal` (an
+  internal serialization fault) — plus `entity` and `id` on the variants that
+  carry them. Branch on `err.kind === "conflict"` instead of matching message
+  text. Callers that matched `String(err)` (e.g.
+  `String(err).startsWith("conflict for")`) must switch to `err.kind` or
+  `err.message`, since `String(err)` is now `"Error: conflict for …"`.
+
 ## [0.4.0] - 2026-08-26
 
 ### Fixed

crates/stitch-wasm/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "stitch-wasm"
-version = "0.4.0"
+version = "0.5.0"
 edition = "2024"
 rust-version = "1.88"
 license = "Apache-2.0"