feat(iios): generic opaque metadata + manual ticket assign (glue prereqs)

Generic kernel primitives so app backends (e.g. a CRM support glue) can link
their domain to interactions WITHOUT the kernel learning any app vocabulary:

- thread: accept an opaque `metadata` bag on create (merged with membership),
  echo it in listThreads, and filter listThreads by `?metadata[key]=value`
  (equality on the opaque bag — the kernel never interprets the keys).
- support: accept opaque `metadata` on createTicket/escalate (thread bag
  inherited); add SupportService.assignTo — a policy-gated manual assignment
  of a ticket to a target actor (POST /v1/support/tickets/:id/assignee).
- SDK @insignia/iios-kernel-client 0.1.2: createThread(metadata),
  listThreads({metadata}) filter, createTicket(metadata), escalate(metadata),
  assignTicket; ThreadSummary/Ticket expose the opaque bag.

Generic-safety gate holds: no crm/customer/lead in kernel code (opaque values
only). Tests: +2 (metadata create/filter, ticket metadata + assignTo); 31 pass.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/iios-kernel-client/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@insignia/iios-kernel-client",
-  "version": "0.1.1",
+  "version": "0.1.2",
   "type": "module",
   "main": "dist/index.js",
   "module": "dist/index.js",