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/examples/acp-demo/tests/built-bin.e2e.ts

@@ -33,7 +33,7 @@ const decompress = promisify(zstdDecompress)
 const dshPackages = [
   'examples/agent-spine-demo', 'core/agent', 'core/session', 'core/system-prompt',
   'core/tools', 'core/agent-loop', 'llm/llm', 'bash/bash',
-  'bash/bash-local', 'bash/tool-bash', 'subprocess/subprocess', 'subprocess/subprocess-local', 'context/workspace-context', 'support/invariants', 'ui/app-boot',
+  'bash/bash-local', 'bash/tool-bash', 'subprocess/subprocess', 'subprocess/subprocess-local', 'context/workspace-context', 'support/invariants', 'boot/app-boot',
   'session/session-persistence',
   'session/session-checkpoint-policy', 'session/session-persistence-jsonl',
   'acp/acp', 'examples/acp-demo', 'util/paths',

packages/examples/acp-demo/tsconfig.json

@@ -18,7 +18,7 @@
       "path": "../../../vendor/loader"
     },
     {
-      "path": "../../ui/app-boot"
+      "path": "../../boot/app-boot"
     },
     {
       "path": "../../acp/acp"

packages/examples/jsonrpc-demo/tsconfig.json

@@ -15,7 +15,7 @@
       "path": "../../../vendor/loader"
     },
     {
-      "path": "../../ui/app-boot"
+      "path": "../../boot/app-boot"
     },
     {
       "path": "../../support/invariants"