feat(schema-form): schema-driven React form renderer package

@deepseek-ai/dsh-client-schema-form rehydrates the wire's serialized
schemastery envelope (new Schema(json)) and edits a draft user section
against it: presence-in-draft marks a field overridden with a per-field
reset, inherited values render as placeholders, role('secret') slots are
write-only with configured-state placeholders from the wire's secrets
list, dict adds take a union-typed sKey as their vocabulary, and any
node the renderer cannot faithfully edit falls back to a read-only view
instead of silently disappearing. renderField(context) is the role hook
the Models page will use for the credential-ref control; validateDraft
runs the same rehydrated validator the host uses, so the browser and
host judge one schema.

packages/client/schema-form/src/invariant.ts

@@ -0,0 +1,32 @@
+/**
+ * Package-owned invariant companion for `@deepseek-ai/dsh-client-schema-form`.
+ * @module @deepseek-ai/dsh-client-schema-form/invariant
+ */
+
+/* jscpd:ignore-start */
+import type { Context } from 'cordis'
+import type { InvariantInstaller } from '@deepseek-ai/dsh-invariants'
+
+const PACKAGE_NAME = '@deepseek-ai/dsh-client-schema-form'
+
+/** Cordis companion plugin name. */
+export const name = 'client-schema-form-invariant'
+/** Service required before the companion can reserve package ownership. */
+export const inject = ['invariants']
+
+/**
+ * No runtime invariant: a pure React rendering library — it emits no cordis
+ * events and owns no cross-plugin mutable relation; draft immutability,
+ * schema rehydration, and control/edit round trips are asserted directly by
+ * this package's component and model specs.
+ */
+const install: InvariantInstaller = () => {}
+
+/**
+ * Register this package's invariant companion.
+ * @param ctx - Cordis context carrying the invariant service.
+ * @returns the installed registration's disposer after setup succeeds.
+ */
+export const apply = (ctx: Context): Promise<() => void> =>
+  Promise.resolve(ctx.invariants.register(PACKAGE_NAME, install))
+/* jscpd:ignore-end */