feat(ui-models): schema-driven provider configuration page

The Models settings section joins llm.providers (the configurable
directory with live state), settings.describe (schemas, layered redacted
values, secret slots), and credentials.describe (value-free badges) into
provider rows with one editor card at a time. The editor renders the
provider's profile subtree through dsh-client-schema-form; the
credential-ref role mounts a control that shows configured/source state
and stores keys write-only through credentials.set. Apply without
removals merges a minimal patch (stored secrets outside it survive);
apply after a reset — and row deletion — replace the user section so
removals land. The client runtime bridges the three new host frames to
typed ctx events (settings/credentials/models changed), the page
refetches on any of them once loaded, and ui-model's per-session picker
directories reload on models/changed so a settings-born route appears in
open pickers without a reopen.

packages/client/runtime/tests/wire-events.spec.ts

@@ -44,6 +44,22 @@ describe('wire event bridge', () => {
     expect(changed).toBe(1)
   })
 
+  it('broadcasts the settings/credentials/models invalidations with their frame payloads', async () => {
+    const bench = await mount()
+    const seen: unknown[][] = []
+    bench.ctx.on('settings/changed', ns => seen.push(['settings', ns]))
+    bench.ctx.on('credentials/changed', ref => seen.push(['credentials', ref]))
+    bench.ctx.on('models/changed', () => seen.push(['models']))
+    bench.sinks?.onHostEnvelope?.({ rpcId: 'r3' as never, payload: { type: 'host/settings-changed', ns: 'llm-pi-ai' } })
+    bench.sinks?.onHostEnvelope?.({ rpcId: 'r4' as never, payload: { type: 'host/credentials-changed', ref: 'OPENAI_API_KEY' } })
+    bench.sinks?.onHostEnvelope?.({ rpcId: 'r5' as never, payload: { type: 'host/models-changed' } })
+    expect(seen).toEqual([
+      ['settings', 'llm-pi-ai'],
+      ['credentials', 'OPENAI_API_KEY'],
+      ['models'],
+    ])
+  })
+
   it('broadcasts connection/reset on every established generation (reconnect invalidation)', async () => {
     const bench = await mount()
     let resets = 0