Replace Type.Any() with Type.Unknown() across all source files

Type.Unknown() is canonical per ADR-012. Both produce identical JSON Schema
output but Unknown communicates intent. Changed in src/graphs/types.ts (metadata,
schema fields) and src/sqlite/tables/{nodes,edges}.ts (AttributesSchema).

src/sqlite/tables/nodes.ts

@@ -4,7 +4,7 @@ import { type Static, Type } from "@alkdev/typebox";
 import { commonCols } from "./common.ts";
 import { graphs } from "./graphs.ts";
 
-const AttributesSchema = Type.Record(Type.String(), Type.Any());
+const AttributesSchema = Type.Record(Type.String(), Type.Unknown());
 
 export const nodes = sqliteTable("nodes", {
   ...commonCols,