capsite/lib: endo's own matcher data, smallcaps, and MapStoreDo

Matchers are now exactly what @endo/patterns makes: tagged records as
from pass-style's makeTagged (M.string() is match:string with payload
[], M.any() is match:any with payload undefined). Structured clone drops
their symbol-keyed and non-enumerable properties, so they cross DO
storage and Workers RPC in marshal's smallcaps encoding (the subset
patterns need).

MapStoreDo is a MapStore as a DO of its own: its creator fixes label and
(encoded) shapes once; its id is full authority, and readOnly() hands
out the queries alone.

Generated-by: Claude Opus 5.5

lib/tests/test-worker.ts

@@ -3,6 +3,8 @@ import { DurableObject } from "cloudflare:workers";
 import { M } from "../src/patterns.js";
 import { makeMapStore, type MapStore } from "../src/store.js";
 
+export { MapStoreDo } from "../src/store-do.js";
+
 /** hosts the store from the credential-rotation sketch: one key, `cookie` */
 export class StoreHost extends DurableObject {
 	cookies(): MapStore<string> {