feat(sdk): P4.5 @insignia/iios-support-web (composes message-web + support REST)

SupportProvider (wraps MessageProvider + support client); useEscalate, useTickets/
useAssignedTickets (+createTicket/patch), useCallbackRequest, useAvailability;
re-exports useThread/useMessages. Boundary allowlist: support-web -> contracts+
kernel-client+message-web+inbox-web.

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

packages/iios-support-web/tsup.config.ts

@@ -0,0 +1,9 @@
+import { defineConfig } from 'tsup';
+
+export default defineConfig({
+  entry: ['src/index.ts'],
+  format: ['esm'],
+  dts: true,
+  clean: true,
+  external: ['react', 'react-dom', '@insignia/iios-message-web', '@insignia/iios-kernel-client'],
+});