WIP prototype migrations

document/migrations/core/Cargo.toml

@@ -0,0 +1,21 @@
+[package]
+name = "migration-core"
+description = "Trait definitions and selectors for Graphite document migrations"
+edition.workspace = true
+version.workspace = true
+license.workspace = true
+authors.workspace = true
+
+[features]
+default = ["typed"]
+# Content-tier migrations over the typed registry. Format-tier-only migration crates
+# (historic version steps, wasm builds) disable this to drop the graph-storage dependency.
+typed = ["dep:graph-storage"]
+
+[dependencies]
+graph-storage = { workspace = true, optional = true }
+
+serde = { workspace = true }
+serde_json = { workspace = true }
+rmp-serde = { workspace = true }
+thiserror = { workspace = true }