Settle the local gates for the model-selector round

- ui-model README pair (short-form Model Experience + audited registry
  entry + Known Limitations), recorded in the pairing manifest
- llm-deepseek README pair rebased onto master's version with this PR's
  real deltas (friendly names, 256k, selector consumers) on both sides;
  runtime/ui-conversation READMEs revert to master (their sections
  documented the removed Session state machine and control slot)
- config catalog regenerated for the ui-model roster row
- ModelDirectory.store JSDoc; ui-model files join the TODO(gui) coverage
  deferral lane beside their ui-command/ui-slash siblings

vitest.config.ts

@@ -133,6 +133,11 @@ export default defineConfig({
         'packages/client/ui-command/src/client/directory.ts',
         'packages/client/ui-command/src/client/service.ts',
         'packages/client/ui-command/src/client/PopupSelectView.tsx',
+        'packages/client/ui-model/src/index.ts',
+        'packages/client/ui-model/src/client/ModelSelect.tsx',
+        'packages/client/ui-model/src/client/directory.ts',
+        'packages/client/ui-model/src/client/index.ts',
+        'packages/client/ui-model/src/client/service.ts',
         'packages/client/ui-slash/src/client/controller.ts',
         'packages/client/ui-slash/src/client/service.ts',
         'packages/client/ui-slash/src/core/menu.ts',