refactor(packages): dissolve ui/ and rename sdk/ to scaffold/

git mv per the regrouping RFC: the five human-collaboration seams and
tui join packages/interaction/, app-boot becomes packages/boot/, and
jsonrpc joins the renamed scaffold/ (formerly sdk/) as its server half
beside client/protocol/create-sdk/helper/scripts/telemetry, whose
folders drop the legacy sdk- prefix. Three new group README triplets
replace the ui/ and sdk/ ones; tsconfig references/paths/globs,
knip keys, vitest globs, gate scripts, catalogs, docs, and the
lockfile follow. Adds the four settled FIXME rename markers
(dsh-sdk-server, dsh-sdk-telemetry, dsh-sdk-helper, dsh-sdk-scripts).

The scaffold folders diverge from their npm names until those renames
land, so tsconfig.base.json maps the three affected names explicitly
beside the group wildcard. Also repairs two pre-existing stale-path
classes the strengthened sweep surfaced: docs/web-styling.md's retired
web-ui host package and type-model spec fixture-literal joins.

app-boot's three Loader-composition specs time out at the default 5s
under full-suite parallel load on this filesystem (pre-existing;
pass isolated with --testTimeout=30000); interaction/scaffold/boot
suites otherwise green (687 passed).

packages/scaffold/helper/src/ids.ts

@@ -0,0 +1,31 @@
+/**
+ * Branded identities owned by the SDK project domain.
+ *
+ * @module @deepseek-ai/dsh-helper/ids
+ */
+
+import type { Branded } from '@deepseek-ai/dsh-brand'
+
+/** Stable identity of a builtin SDK feature. */
+export type FeatureId = Branded<'FeatureId'>
+
+/**
+ * Construct a feature identity from its registry key.
+ * @param value - lowercase kebab-case registry key.
+ * @returns branded feature identity.
+ */
+export function featureId(value: string): FeatureId {
+  if (!/^[a-z][a-z0-9-]*$/.test(value)) {
+    throw new Error(`invalid feature id: ${JSON.stringify(value)}`)
+  }
+  return value as FeatureId
+}
+
+/** Stable identity of a resource contributed to an SDK project. */
+export type ResourceKey = Branded<'ResourceKey'>
+
+/** Construct a resource key from its owner-qualified value. */
+export function resourceKey(value: string): ResourceKey {
+  if (value.length === 0) throw new Error('resource key must not be empty')
+  return value as ResourceKey
+}